bims-drudre Biomed News
on Targeted drug delivery and programmed release mechanisms
Issue of 2021‒05‒30
fifteen papers selected by
Ceren Kimna
Technical University of Munich
  1. BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in humans.
  2. Partial recovery of visual function in a blind patient after optogenetic therapy.
  3. Traceable Nano-Biohybrid Complexes by One-Step Synthesis as CRISPR-Chem Vectors for Neurodegenerative Diseases Synergistic Treatment.
  4. Mitochondrial targeted meganuclease as a platform to eliminate mutant mtDNA in vivo.
  5. Nanoparticle-mediated convection-enhanced delivery of a DNA intercalator to gliomas circumvents temozolomide resistance.
  6. Multifunctional biomolecule nanostructures for cancer therapy.
  7. A 3D Fiber-Hydrogel Based Non-Viral Gene Delivery Platform Reveals that microRNAs Promote Axon Regeneration and Enhance Functional Recovery Following Spinal Cord Injury.
  8. Tissue-engineered vascular microphysiological platform to study immune modulation of xenograft rejection.
  9. Nanoengineered Peptide-Based Antimicrobial Conductive Supramolecular Biomaterial for Cardiac Tissue Engineering.
  10. Modulation of Gastrointestinal Mucus Properties with Ionic Liquids for Drug Delivery.
  11. Sonosensitizer-Functionalized Graphene Nanoribbons for Adhesion Blocking and Sonodynamic Ablation of Ovarian Cancer Spheroids.
  12. Self-assembly of protein superstructures by physical interactions under cytoplasm-like conditions.
  13. Enhanced Delivery of Neuroactive Drugs via Nasal Delivery with a Self-Healing Supramolecular Gel.
  14. Advances in Application of Azobenzene as a Trigger in Biomedicine: Molecular Design and Spontaneous Assembly.
  15. Bubble Forming Films for Spatial Selective Cell Killing.
  1. Nature. 2021 May 27.
    BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in humans.
    Ugur Sahin, Alexander Muik, Isabel Vogler, Evelyna Derhovanessian, Lena M Kranz, Mathias Vormehr, Jasmin Quandt, Nicole Bidmon, Alexander Ulges, Alina Baum, Kristen E Pascal, Daniel Maurus, Sebastian Brachtendorf, Verena Lörks, Julian Sikorski, Peter Koch, Rolf Hilker, Dirk Becker, Ann-Kathrin Eller, Jan Grützner, Manuel Tonigold, Carsten Boesler, Corinna Rosenbaum, Ludwig Heesen, Marie-Cristine Kühnle, Asaf Poran, Jesse Z Dong, Ulrich Luxemburger, Alexandra Kemmer-Brück, David Langer, Martin Bexon, Stefanie Bolte, Tania Palanche, Armin Schultz, Sybille Baumann, Azita J Mahiny, Gábor Boros, Jonas Reinholz, Gábor T Szabó, Katalin Karikó, Pei-Yong Shi, Camila Fontes-Garfias, John L Perez, Mark Cutler, David Cooper, Christos A Kyratsous, Philip R Dormitzer, Kathrin U Jansen, Özlem Türeci.
      BNT162b2, a lipid nanoparticle (LNP) formulated nucleoside-modified messenger RNA (mRNA) that encodes the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike glycoprotein (S) stabilized in the prefusion conformation, has demonstrated 95% efficacy in preventing coronavirus disease-19 (COVID-19)1. Here we extend our previous phase 1/2 trial report2 and present BNT162b2 prime/boost induced immune response data from a second phase 1/2 trial in healthy adults (18-55 years of age). BNT162b2 elicited strong antibody responses, with SARS-CoV-2 serum 50% neutralizing geometric mean titers up to 3.3-fold above those observed in COVID-19 human convalescent samples (HCS) one week post-boost. BNT162b2-elicited sera neutralized 22 pseudoviruses bearing SARS-CoV-2 S variants. Most participants had a strong IFNγ- or IL-2-positive CD8+ and CD4+ T helper type 1 (TH1) T cell response, detectable throughout the full observation period of nine weeks following the boost. pMHC multimer technology identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week post-boost, epitope-specific CD8+ T cells of the early differentiated effector-memory phenotype comprised 0.02-2.92% of total circulating CD8+ T cells and were detectable (0.01-0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes conserved in a broad range of variants at well tolerated doses.
    DOI:  https://doi.org/10.1038/s41586-021-03653-6
  2. Nat Med. 2021 May 24.
    Partial recovery of visual function in a blind patient after optogenetic therapy.
    José-Alain Sahel, Elise Boulanger-Scemama, Chloé Pagot, Angelo Arleo, Francesco Galluppi, Joseph N Martel, Simona Degli Esposti, Alexandre Delaux, Jean-Baptiste de Saint Aubert, Caroline de Montleau, Emmanuel Gutman, Isabelle Audo, Jens Duebel, Serge Picaud, Deniz Dalkara, Laure Blouin, Magali Taiel, Botond Roska.
      Optogenetics may enable mutation-independent, circuit-specific restoration of neuronal function in neurological diseases. Retinitis pigmentosa is a neurodegenerative eye disease where loss of photoreceptors can lead to complete blindness. In a blind patient, we combined intraocular injection of an adeno-associated viral vector encoding ChrimsonR with light stimulation via engineered goggles. The goggles detect local changes in light intensity and project corresponding light pulses onto the retina in real time to activate optogenetically transduced retinal ganglion cells. The patient perceived, located, counted and touched different objects using the vector-treated eye alone while wearing the goggles. During visual perception, multichannel electroencephalographic recordings revealed object-related activity above the visual cortex. The patient could not visually detect any objects before injection with or without the goggles or after injection without the goggles. This is the first reported case of partial functional recovery in a neurodegenerative disease after optogenetic therapy.
    DOI:  https://doi.org/10.1038/s41591-021-01351-4
  3. Adv Mater. 2021 May 28. e2101993
    Traceable Nano-Biohybrid Complexes by One-Step Synthesis as CRISPR-Chem Vectors for Neurodegenerative Diseases Synergistic Treatment.
    Jie Shen, Zhiguo Lu, Jianze Wang, Qiulian Hao, Weihong Ji, Yanyue Wu, Huan Peng, Ruichen Zhao, Jun Yang, Yan Li, Zhuyan Shi, Xin Zhang.
      Abnormal protein aggregations are essential pathological features of neurodegenerative diseases. Eliminating while inhibiting the regeneration of these protein aggregates is considered an effective treatment strategy. Herein, the CRISPR/Cas9 gene-editing tool is employed to inhibit the regeneration of disease-related proteins, while chemical drugs are applied to eliminate the proteins that are produced. To efficiently deliver CRISPR-chem drugs into brain lesions, traceable nano-biohybrid complexes (F-TBIO) are constructed by one-step synthesis and CRISPR/Cas9 plasmids (CF-TBIO) are loaded in a controllable manner. CF-TBIO can knock out the BACE1 gene and reduce the burden of amyloid-β, and thereby significantly improve the cognitive abilities of 2xTg-AD mice. In particular, by prolonging the dosing interval, the pathological damage and behavioral abilities of 2xTg-AD mice are still significantly improved. During the therapeutic process, CF-TBIO with a high relaxation rate provides accurate imaging signals in the complex brain physiological environment. The finding shows that CF-TBIO has great potential to serve as a CRISPR-chem drug-delivery platform for neurodegenerative diseases therapy.
    Keywords:  CRISPR-chem vectors; CRISPR/Cas9; neurodegenerative diseases synergistic treatment; one-step synthesis; traceable nano-biohybrid complexes
    DOI:  https://doi.org/10.1002/adma.202101993
  4. Nat Commun. 2021 May 28. 12(1): 3210
    Mitochondrial targeted meganuclease as a platform to eliminate mutant mtDNA in vivo.
    Ugne Zekonyte, Sandra R Bacman, Jeff Smith, Wendy Shoop, Claudia V Pereira, Ginger Tomberlin, James Stewart, Derek Jantz, Carlos T Moraes.
      Diseases caused by heteroplasmic mitochondrial DNA mutations have no effective treatment or cure. In recent years, DNA editing enzymes were tested as tools to eliminate mutant mtDNA in heteroplasmic cells and tissues. Mitochondrial-targeted restriction endonucleases, ZFNs, and TALENs have been successful in shifting mtDNA heteroplasmy, but they all have drawbacks as gene therapy reagents, including: large size, heterodimeric nature, inability to distinguish single base changes, or low flexibility and effectiveness. Here we report the adaptation of a gene editing platform based on the I-CreI meganuclease known as ARCUS®. These mitochondrial-targeted meganucleases (mitoARCUS) have a relatively small size, are monomeric, and can recognize sequences differing by as little as one base pair. We show the development of a mitoARCUS specific for the mouse m.5024C>T mutation in the mt-tRNAAla gene and its delivery to mice intravenously using AAV9 as a vector. Liver and skeletal muscle show robust elimination of mutant mtDNA with concomitant restoration of mt-tRNAAla levels. We conclude that mitoARCUS is a potential powerful tool for the elimination of mutant mtDNA.
    DOI:  https://doi.org/10.1038/s41467-021-23561-7
  5. Nat Biomed Eng. 2021 May 27.
    Nanoparticle-mediated convection-enhanced delivery of a DNA intercalator to gliomas circumvents temozolomide resistance.
    Yongheng Wang, Yuhang Jiang, Dengshuai Wei, Priya Singh, Yingjie Yu, Teresa Lee, Lingpu Zhang, Hanna K Mandl, Alexandra S Piotrowski-Daspit, Xinyuan Chen, Fan Li, Xing Li, Yiyu Cheng, Alexander Josowitz, Fan Yang, Yao Zhao, Fuyi Wang, Zhenwen Zhao, Anita Huttner, Ranjit S Bindra, Haihua Xiao, W Mark Saltzman.
      In patients with glioblastoma, resistance to the chemotherapeutic temozolomide (TMZ) limits any survival benefits conferred by the drug. Here we show that the convection-enhanced delivery of nanoparticles containing disulfide bonds (which are cleaved in the reductive environment of the tumour) and encapsulating an oxaliplatin prodrug and a cationic DNA intercalator inhibit the growth of TMZ-resistant cells from patient-derived xenografts, and hinder the progression of TMZ-resistant human glioblastoma tumours in mice without causing any detectable toxicity. Genome-wide RNA profiling and metabolomic analyses of a glioma cell line treated with the cationic intercalator or with TMZ showed substantial differences in the signalling and metabolic pathways altered by each drug. Our findings suggest that the combination of anticancer drugs with distinct mechanisms of action with selective drug release and convection-enhanced delivery may represent a translational strategy for the treatment of TMZ-resistant gliomas.
    DOI:  https://doi.org/10.1038/s41551-021-00728-7
  6. Nat Rev Mater. 2021 May 19. 1-18
    Multifunctional biomolecule nanostructures for cancer therapy.
    Jing Wang, Yiye Li, Guangjun Nie.
      Biomolecule-based nanostructures are inherently multifunctional and harbour diverse biological activities, which can be explored for cancer nanomedicine. The supramolecular properties of biomolecules can be precisely programmed for the design of smart drug delivery vehicles, enabling efficient transport in vivo, targeted drug delivery and combinatorial therapy within a single design. In this Review, we discuss biomolecule-based nanostructures, including polysaccharides, nucleic acids, peptides and proteins, and highlight their enormous design space for multifunctional nanomedicines. We identify key challenges in cancer nanomedicine that can be addressed by biomolecule-based nanostructures and survey the distinct biological activities, programmability and in vivo behaviour of biomolecule-based nanostructures. Finally, we discuss challenges in the rational design, characterization and fabrication of biomolecule-based nanostructures, and identify obstacles that need to be overcome to enable clinical translation.
    Keywords:  Cancer therapy; Nanotechnology in cancer
    DOI:  https://doi.org/10.1038/s41578-021-00315-x
  7. Adv Sci (Weinh). 2021 May 29. e2100805
    A 3D Fiber-Hydrogel Based Non-Viral Gene Delivery Platform Reveals that microRNAs Promote Axon Regeneration and Enhance Functional Recovery Following Spinal Cord Injury.
    Na Zhang, Junquan Lin, Vincent Po Hen Lin, Ulla Milbreta, Jiah Shin Chin, Elaine Guo Yan Chew, Michelle Mulan Lian, Jia Nee Foo, Kunyu Zhang, Wutian Wu, Sing Yian Chew.
      Current treatment approaches toward spinal cord injuries (SCI) have mainly focused on overcoming the inhibitory microenvironment that surrounds lesion sites. Unfortunately, the mere modulation of the cell/tissue microenvironment is often insufficient to achieve desired functional recovery. Therefore, stimulating the intrinsic growth ability of injured neurons becomes crucial. MicroRNAs (miRs) play significant roles during axon regeneration by regulating local protein synthesis at growth cones. However, one challenge of using miRs to treat SCI is the lack of efficient delivery approaches. Here, a 3D fiber-hydrogel scaffold is introduced which can be directly implanted into a spinal cord transected rat. This 3D scaffold consists of aligned electrospun fibers which provide topographical cues to direct axon regeneration, and collagen matrix which enables a sustained delivery of miRs. Correspondingly, treatment with Axon miRs (i.e., a cocktail of miR-132/miR-222/miR-431) significantly enhances axon regeneration. Moreover, administration of Axon miRs along with anti-inflammatory drug, methylprednisolone, synergistically enhances functional recovery. Additionally, this combined treatment also decreases the expression of pro-inflammatory genes and enhance gene expressions related to extracellular matrix deposition. Finally, increased Axon miRs dosage with methylprednisolone, significantly promotes functional recovery and remyelination. Altogether, scaffold-mediated Axon miR treatment with methylprednisolone is a promising therapeutic approach for SCI.
    Keywords:  RNA interference; RNA sequencing; electrospinning; hydrogel; neural tissue engineering
    DOI:  https://doi.org/10.1002/advs.202100805
  8. Sci Adv. 2021 May;pii: eabg2237. [Epub ahead of print]7(22):
    Tissue-engineered vascular microphysiological platform to study immune modulation of xenograft rejection.
    Tae Hee Kim, Ji-Jing Yan, Joon Young Jang, Gwang-Min Lee, Sun-Kyung Lee, Beom Seok Kim, Justin J Chung, Soo Hyun Kim, Youngmee Jung, Jaeseok Yang.
      Most of the vascular platforms currently being studied are lab-on-a-chip types that mimic capillary networks and are applied for vascular response analysis in vitro. However, these platforms have a limitation in clearly assessing the physiological phenomena of native blood vessels compared to in vivo evaluation. Here, we developed a simply fabricable tissue-engineered vascular microphysiological platform (TEVMP) with a three-dimensional (3D) vascular structure similar to an artery that can be applied for ex vivo and in vivo evaluation. Furthermore, we applied the TEVMP as ex vivo and in vivo screening systems to evaluate the effect of human CD200 (hCD200) overexpression in porcine endothelial cells (PECs) on vascular xenogeneic immune responses. These screening systems, in contrast to 2D in vitro and cellular xenotransplantation in vivo models, clearly demonstrated that hCD200 overexpression effectively suppressed vascular xenograft rejection. The TEVMP has a high potential as a platform to assess various vascular-related responses.
    DOI:  https://doi.org/10.1126/sciadv.abg2237
  9. Adv Mater. 2021 May 25. e2008715
    Nanoengineered Peptide-Based Antimicrobial Conductive Supramolecular Biomaterial for Cardiac Tissue Engineering.
    Priyadarshi Chakraborty, Hadas Oved, Darya Bychenko, Yifei Yao, Yiming Tang, Shai Zilberzwige-Tal, Guanghong Wei, Tal Dvir, Ehud Gazit.
      Owing to their dynamic nature and ordered architecture, supramolecular materials strikingly resemble organic components of living systems. Although short-peptide self-assembled nanostructured hydrogels are regarded as intriguing supramolecular materials for biotechnology, their application is often limited due to their low stability and considerable challenge of combining other desirable properties. Herein, a di-Fmoc-based hydrogelator containing the cell-adhesive Arg-Gly-Asp (RGD) fragment that forms a mechanically stable, self-healing hydrogel is designed. Molecular dynamics simulation reveals the presence of RGD segments on the surface of the hydrogel fibers, highlighting their cell adherence capacity. Aiming to impart conductivity, the 3D network of the hydrogel is further nanoengineered by incorporating polyaniline (PAni). The composite hydrogels demonstrate semiconductivity, excellent antibacterial activity, and DNA binding capacity. Cardiac cells grown on the surface of the composite hydrogels form functional synchronized monolayers. Taken together, the combination of these attributes in a single hydrogel suggests it as an exceptional candidate for functional supramolecular biomaterial designed for electrogenic tissue engineering.
    Keywords:  antibacterial properties; biomaterials; cardiac tissue engineering; hydrogels; peptides; polyaniline
    DOI:  https://doi.org/10.1002/adma.202008715
  10. Adv Healthc Mater. 2021 May 29. e2002192
    Modulation of Gastrointestinal Mucus Properties with Ionic Liquids for Drug Delivery.
    Kevin Peng, Yongsheng Gao, Pavimol Angsantikul, Anthony LaBarbiera, Morgan Goetz, Alexander M Curreri, Danika Rodrigues, Eden E L Tanner, Samir Mitragotri.
      The mucus barrier lining the gastrointestinal tract poses a significant barrier to the oral delivery of macromolecular drugs. Successful approaches to overcoming this barrier have primarily focused on reducing drug and carrier interactions with mucus or disrupting the mucus layer directly. Choline-based ionic liquids (ILs) such as choline geranate and choline glycolate (CGLY) have recently been shown to be effective in enhancing the intestinal absorption of macromolecules such as insulin and immunoglobulin (IgG), respectively. Herein, the use of choline-based ILs as mucus-modulating agents for safely improving drug penetration through mucus is described. Choline-based ILs significantly increase the diffusion rates of cationic dextrans through mucin solution. Choline-maleic acid (CMLC 2:1) enhances the diffusion of 4 kDa cationic dextran in mucin solution by more than fourfold when compared to phosphate-buffered saline control. Choline-based ILs also reduce mucus viscosity without significantly impacting the native mucus gel structure. In vitro studies in a mucus-secreting coculture model with Caco-2 and HT29MTX-E12 cells further demonstrate the effectiveness of ILs in improving transport of cationic molecules in the presence of secreted mucus. This work demonstrates the potential for choline-based ionic liquids to be used as nondestructive mucus-modulating agents for enabling enhanced oral delivery of macromolecular drugs.
    Keywords:  diffusion; ionic liquids; mucosal; mucus; viscosity
    DOI:  https://doi.org/10.1002/adhm.202002192
  11. Adv Healthc Mater. 2021 May 29. e2001368
    Sonosensitizer-Functionalized Graphene Nanoribbons for Adhesion Blocking and Sonodynamic Ablation of Ovarian Cancer Spheroids.
    Hak Rae Lee, Dae Woo Kim, Victoria O Jones, Yunkyu Choi, Vivian E Ferry, Melissa A Geller, Samira M Azarin.
      Advanced stage ovarian cancer is challenging to treat due to widespread seeding of tumor spheroids throughout the mesothelial lining of the peritoneal cavity. In this work, a therapeutic strategy using graphene nanoribbons (GNR) functionalized with 4-arm polyethylene glycol (PEG) and chlorin e6 (Ce6), a sonosensitizer, to target metastatic ovarian cancer spheroids is reported. GNR-PEG-Ce6 adsorbs onto the spheroids and disrupts their adhesion to extracellular matrix proteins or LP-9 mesothelial cells. Furthermore, for spheroids that do adhere, GNR-PEG-Ce6 delays spheroid disaggregation and spreading as well as mesothelial clearance, key metastatic processes following adhesion. Owing to the sonodynamic effects of Ce6 and its localized delivery via the biomaterial, GNR-PEG-Ce6 can kill ovarian cancer spheroids adhered to LP-9 cell monolayers when combined with mild ultrasound irradiation. The interaction with GNR-PEG-Ce6 also loosens cell-cell adhesions within the spheroids, rendering them more susceptible to treatment with the chemotherapeutic agents cisplatin and paclitaxel, which typically have difficulty in penetrating ovarian cancer spheroids. Thus, this material can facilitate effective chemotherapeutic and sonodynamic combination therapies. Finally, the adhesion inhibiting and sonodynamic effects of GNR-PEG-Ce6 are also validated with tumor spheroids derived from the ascites fluid of ovarian cancer patients, providing evidence of the translational potential of this biomaterial approach.
    Keywords:  graphene nanoribbons; graphene oxide; ovarian cancer; sonodynamic therapy; ultrasound irradiation
    DOI:  https://doi.org/10.1002/adhm.202001368
  12. Biophys J. 2021 May 19. pii: S0006-3495(21)00421-5. [Epub ahead of print]
    Self-assembly of protein superstructures by physical interactions under cytoplasm-like conditions.
    Yuxing Yao, Zhiyang Jin, Bill Ling, Dina Malounda, Mikhail G Shapiro.
      The structure-driven assembly of multimeric protein complexes and the formation of intracellular phase-like protein condensates have been the subject of intense research. However, the assembly of larger superstructures comprising cellular components such as protein nanoparticles driven by general physical rather than specific biochemical interactions remain relatively uncharacterized. Here, we use gas vesicles (GVs) - genetically encoded protein nanoparticles that form ordered intracellular clusters - as a model system to study the forces driving multi-particle assembly under cytoplasm-like conditions. Our calculations and experimental results show that the ordered assembly of GVs can be achieved by screening their mutual electrostatic repulsion with electrolytes and creating a crowding force with dissolved macromolecules. The precise balance of these forces results in different packing configurations. Biomacromolecules such as polylysine and DNA are capable of driving GV clustering. These results provide basic insights into how physically driven interactions affect the formation of protein superstructures, offer guidance for manipulating nanoparticle assembly in cellular environments through synthetic biology methods, and inform research on the biotechnology applications of GVs.
    Keywords:  Gas vesicles; Physical interactions; Self-assembly
    DOI:  https://doi.org/10.1016/j.bpj.2021.05.007
  13. Adv Sci (Weinh). 2021 May 24. e2101058
    Enhanced Delivery of Neuroactive Drugs via Nasal Delivery with a Self-Healing Supramolecular Gel.
    Julie Tzu-Wen Wang, Ana C Rodrigo, Anna K Patterson, Kirsten Hawkins, Mazen M S Aly, Jia Sun, Khuloud T Al Jamal, David K Smith.
      This paper reports the use of a self-assembling hydrogel as a delivery vehicle for the Parkinson's disease drug l-DOPA. Based on a two-component combination of an l-glutamine amide derivative and benzaldehyde, this gel has very soft rheological properties and self-healing characteristics. It is demonstrated that the gel can be formulated to encapsulate l-DOPA. These drug-loaded gels are characterized, and rapid release of the drug is obtained from the gel network. This drug-loaded hydrogel has appropriate rheological characteristics to be amenable for injection. This system is therefore tested as a vehicle for nasal delivery of neurologically-active drugs-a drug delivery strategy that can potentially avoid first pass liver metabolism and bypass the blood-brain barrier, hence enhancing brain uptake. In vitro tests indicate that the gel has biocompatibility with respect to nasal epithelial cells. Furthermore, animal studies demonstrate that the nasal delivery of a gel loaded with 3 H-labeled l-DOPA out-performed a simple intranasal l-DOPA solution. This is attributed to longer residence times of the gel in the nasal cavity resulting in increased blood and brain concentrations. It is demonstrated that the likely routes of brain penetration of intranasally-delivered l-DOPA gel involve the trigeminal and olfactory nerves connecting to other brain regions.
    Keywords:  drug delivery; hydrogel; neuroactive drugs, supramolecular gel
    DOI:  https://doi.org/10.1002/advs.202101058
  14. Adv Mater. 2021 May 24. e2007290
    Advances in Application of Azobenzene as a Trigger in Biomedicine: Molecular Design and Spontaneous Assembly.
    Hong-Bo Cheng, Shuchun Zhang, Ji Qi, Xing-Jie Liang, Juyoung Yoon.
      Azobenzene is a well-known derivative of stimulus-responsive molecular switches and has shown superior performance as a functional material in biomedical applications. The results of multiple studies have led to the development of light/hypoxia-responsive azobenzene for biomedical use. In recent years, long-wavelength-responsive azobenzene has been developed. Matching the longer wavelength absorption and hypoxia-response characteristics of the azobenzene switch unit to the bio-optical window results in a large and effective stimulus response. In addition, azobenzene has been used as a hypoxia-sensitive connector via biological cleavage under appropriate stimulus conditions. This has resulted in on/off state switching of properties such as pharmacology and fluorescence activity. Herein, recent advances in the design and fabrication of azobenzene as a trigger in biomedicine are summarized.
    Keywords:  azobenzene; bio-optical windows; biomedicine; hypoxia; photoswitches
    DOI:  https://doi.org/10.1002/adma.202007290
  15. Adv Mater. 2021 May 29. e2008379
    Bubble Forming Films for Spatial Selective Cell Killing.
    Dawei Hua, Aranit Harizaj, Mike Wels, Toon Brans, Stephan Stremersch, Herlinde De Keersmaecker, Eduardo Bolea-Fernandez, Frank Vanhaecke, Dimitri Roels, Kevin Braeckmans, Ranhua Xiong, Chaobo Huang, Stefaan C De Smedt, Félix Sauvage.
      Photodynamic and photothermal cell killing at the surface of tissues finds applications in medicine. However, a lack of control over heat dissipation following a treatment with light might damage surrounding tissues. A new strategy to kill cells at the surface of tissues is reported. Polymeric films are designed in which iron oxide nanoparticles are embedded as photosensitizers. Irradiation of the films with pulsed laser light generates water vapor bubbles at the surface of the films. It is found that "bubble-films" can kill cells in close proximity to the films due to mechanical forces which arise when the bubbles collapse. Local irradiation of bubble-films allows for spatial selective single cell killing. As nanosurgery becomes attractive in ophthalmology to remove superficial tumors, bubble-films are applied on the cornea and found that irradiation of the bubble-films allows spatial and selective killing of corneal cells. As i) the photosensitizer is embedded in the films, which reduces its uptake by cells and spreading into tissues and ii) the bubble-films can be removed from the tissue after laser treatment, while iii) a low laser fluence is sufficient to generate vapor bubbles, it is foreseen that bubble-films might become promising for safe resection of superficial tumors.
    Keywords:  cornea; nanosurgery; photoablation; photodynamic therapy; single cell killing
    DOI:  https://doi.org/10.1002/adma.202008379
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