Cancer immunotherapy involves a cascade of events that ultimately leads to cytotoxic immune cells effectively identifying and destroying cancer cells. Responsive nanomaterials, which enable spatiotemporal orchestration of various immunological events for mounting a highly potent and long-lasting antitumor immune response, are an attractive platform to overcome challenges associated with existing cancer immunotherapies. Here, we report a multifunctional near-infrared (NIR)-responsive core–shell nanoparticle, which enables (i) photothermal ablation of cancer cells for generating tumor-associated antigen (TAA) and (ii) triggered release of an immunomodulatory drug (gardiquimod) for starting a series of immunological events. The core of these nanostructures is composed of a polydopamine nanoparticle, which serves as a photothermal agent, and the shell is made of mesoporous silica, which serves as a drug carrier. We employed a phase-change material as a gatekeeper to achieve concurrent release of both TAA and adjuvant, thus efficiently activating the antigen-presenting cells. Photothermal immunotherapy enabled by these nanostructures resulted in regression of primary tumor and significantly improved inhibition of secondary tumor in a mouse melanoma model. These biocompatible, biodegradable, and NIR-responsive core–shell nanostructures simultaneously deliver payload and cause photothermal ablation of the cancer cells. Our results demonstrate potential of responsive nanomaterials in generating highly synergistic photothermal immunotherapeutic response.
Graphene oxide-silk composites have gained a significant interest in the recent times because of the unique mechanical properties of both GO and silk and their ability to form layered structures that exhibit a striking resemblance to the layered (brick-mortar) composites found in nature. However, various aspects of the interaction between silk and graphene oxide (e.g., conformation and distribution of the silk chains on chemically heterogeneous GO surface) are not completely understood. In this study, we demonstrate that the interaction between the silk fibroin chains and GO can be modulated by altering the pH of the silk fibroin solution. We employed atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy to probe the distribution and the secondary structure of silk fibroin adsorbed on GO. In acidic pH conditions (i.e., pH < pI), a high density of silk chains were found to adsorb on the GO surface, whereas an increase in pH resulted in a progressive decrease in the density of the adsorbed silk chains. This pH-dependent adsorption is ascribed to the electrostatic interactions between the negatively charged GO surface and the tunable ionization of the silk molecules. The secondary structure of silk fibroin chains adsorbed on GO was also found to be highly dependent on the pH. This study provides a deeper understanding of the interaction between GO and silk fibroin that is critical for the design and fabrication of bioinspired nanocomposites with tailored mechanical properties.
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text S. Singamaneni, "Plasmonic Biosensors with Ultrastable Biorecognition Elements," in Advanced Photonics 2017 (IPR, NOMA, Sensors, Networks, SPPCom, PS), OSA Technical Digest (online) (Optica Publishing Group, 2017), paper SeTu3D.3. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article
We report a novel surface enhanced Raman Scattering (SERS) substrate platform based on a common filter paper adsorbed with plasmonic nanostructures. Paper based SERS substrate overcomes many of the challenges associated with conventional SERS substrates based on rigid substrates such as silicon and glass. The paper-based design results in a substrate that combines all of the advantages of conventional rigid and planar SERS substrates in a dynamic flexible scaffolding format. We discuss the fabrication, physical characterization and SERS activity of our novel substrates using non-resonant analytes.
A wide range of conventional immunoassays and emerging biosensors rely on antibodies, which are required to be maintained under tightly regulated temperature (refrigerated) conditions, to preserve their biofunctionality (recognition capability). This stringent requirement necessitates a "cold chain" system during transportation and storage, which is usually impractical in resource-limited settings. Here, we introduce two types of materials, zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), and silk fibroin, extracted from silk cocoon, to form protective coatings to preserve the antibody recognition capability on biochips under ambient and elevated temperatures. Formation of these protective coatings is easy, and a simple water rinsing step can restore the biofunctionality of the coated biochip, thereby making it highly convenient for use in point-of-care and resource-limited settings. A plasmonic nanobiosensor is employed as a transduction platform for monitoring the formation and removal of the protective coatings and to quantify the biopreservation ability of these coatings under various extreme storage conditions. We believe this energy-efficient and environmentally-friendly approach eliminates the needs for cold chain and temperature-controlled storage/shipping of diagnostic reagents and materials, thereby extending the capability of antibody-based biosensors to various resource-limited environments. More broadly, these protective coatings are expected to play a powerful role in the realization of ultrastable biodiagnostics and therapeutics. We will also present a novel class of plasmonic biosensors that rely on artificial antibodies or peptide recognition elements with excellent temperature and chemical stability. These multi-pronged approaches overcome the poor stability of existing plasmonic biosensors or other types of antibody-based biosensors and take them closer to real-world applications in resource-limited settings.
The cover shows an SEM image of a periodic porous SU8 microframe decorated with gold nanoparticles. On p. 1369, Vladimir Tsukruk and co-workers demonstrate a biomediated approach for the metallization of periodic, porous polymer microstructures fabricated using interference lithography. The direct growth of metal nanoparticles does not damage or modify the original structure, making the approach demonstrated here highly suitable for designing reinforced binary microcomposites with predetermined symmetry.
ABSTRACT Stand-off chemical sensing is an important capability with applications in several domains including homeland security. Engineered devices for this task, popularly referred to as electronic noses, have limited capacity compared to the broad-spectrum abilities of the biological olfactory system. Therefore, we propose a hybrid bio-electronic solution that directly takes advantage of the rich repertoire of olfactory sensors and sophisticated neural computational framework available in an insect olfactory system. We show that select subsets of neurons in the locust ( Schistocerca americana ) brain were activated upon exposure to various explosive chemical species (such as DNT and TNT). Responses from an ensemble of neurons provided a unique, multivariate fingerprint that allowed discrimination of explosive vapors from non-explosive chemical species and from each other. Notably, target chemical recognition could be achieved within a few hundred milliseconds of exposure. Finally, we developed a minimally-invasive surgical approach and mobile multi-unit electrophysiological recording system to tap into the neural signals in a locust brain and realize a biorobotic explosive sensing system. In sum, our study provides the first demonstration of how biological olfactory systems (sensors and computations) can be hijacked to develop a cyborg chemical sensing approach. SUMMARY We demonstrate a bio-robotic chemical sensing approach where signals from an insect brain are directly utilized to detect and distinguish various explosive chemical vapors.
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