Tricompartmental Microcarriers with Controlled Release for Efficient Management of Parkinson's Disease.

Parkinson's is a progressive neurodegenerative disease of the nervous system. It has no cure, but its symptoms can be managed by supplying dopamine artificially to the brain.This work aims to engineer tricompartmental polymeric microcarriers by electrohydrodynamic cojetting technique to encapsulate three PD (Parkinson's disease) drugs incorporated with high encapsulation efficiency (∼100%) in a single carrier at a fixed drug ratio of 4:1:8 (Levodopa (LD): Carbidopa(CD): Entacapone (ENT)). Upon oral administration, the drug ratio needs to be maintained during subsequent release from microparticles to enhance the bioavailability of primary drug LD. This presents a notable challenge, as the three drugs vary in their aqueous solubility (LD > CD > ENT). The equilibrium of therapeutic release was achieved using a combination of FDA-approved polymers (PLA, PLGA, PCL, and PEG) and the disc shape of particles. In vitro studies demonstrated the simultaneous release of all the three therapeutics in a sustained and controlled manner. Additionally, pharmacodynamics and pharmacokinetics studies in Parkinson's disease rats induced by rotenone showed a remarkable improvement in PD conditions for the microparticles-fed rats, thereby showing a great promise toward efficient management of PD.

Evolution Kinetics of Stabilizing Pickering Emulsion by Brush-Modified Janus Particles: DPD Simulation and Experimental Insights.

In the present study, we report the evolution of stabilizing Pickering emulsions using brush-modified Janus particles (JPs), utilizing the dissipative particle dynamics (DPD) simulation technique. Our results are subsequently corroborated with experimental findings. Each JP has one-half of the hydrophobic surface, with the other half embedded with hydrophilic polymer brushes grown via atom transfer radical polymerization (ATRP). Our generic simulation model analyzes the chemical kinetics of polymer brush growth on one-half of the initiator-embedded microparticle (MP) surface, resulting in the formation of JP. This involves evaluating monomer conversion and reaction rates. Our results exhibit a substantial influence of the number of JPs, grafted brush density, and brush length on oil-in-water emulsion stability. We studied the evolution kinetics and stability of emulsion formation by analyzing the growth of average domain size and corresponding scaling functions up to a late time limit. This study aims to clarify the connection between the size, quantity, and functionality of JPs and the stability of Pickering emulsions.

Architecture dependent transport behavior of iron (0) entrapped biodegradable polymeric particles for groundwater remediation.

Polylactic acid based spherical particles with three architectural variations (Isotropic (P1), Semi porous (P2), and Janus (P3)) were employed to encapsulate zero valent iron nanoparticles (ZVINPs), and their performance was extensively evaluated in our previous studies. However, little was known about their transportability through saturated porous media of varying grain size kept under varying ionic strength. In this particular study, we aimed to investigate the architectural effect of polymeric particles (P1-P3) on their mobility through the sand column of varying grain size in presence of mono, di, and tri-valent ions of varying concentrations (25-200 mM (millimoles)). As per column breakthrough experiments (BTCs) using various types of sands, amphiphilic Janus type (P3) particles exhibited the maximum transportability among all the tested particles, irrespective of the nature of the sand. Owing to the narrower travel path, sands with lower porosity (31%) delayed the plateau by shifting it to a higher pore volume with a minimum retention of iron (C/Co: 0.94 for P3) in the column. The impact of mono (Na+, K+), di (Ca2+, Mg2+), and trivalent (Al3+) ions on their transportability was progressively increased from P3 to P1, especially at higher ionic concentrations (200 mM), with P3 being the most mobile particles (C/Co:0.54 for Al3+). Among all the ions, Al3+ exhibited maximum hindrance to their mobility through the sand column. This could be due to their strong charge screening effect coupled with cation bridging complex formation with moving particles. Experimental results obtained from BTCs were found to be well-fitted with a theoretical model based on advection-dispersion equation, showing minimum retention for P3 particles. Overall, it can be inferred that encapsulation of ZVINPs inside Janus particles (P3) with a right balance of amphiphilicity and highly negative surface charge would be required to achieve considerable transportability through sand aquifers to target contaminants in polluted groundwater existing under harsh conditions (high ionic concentrations).

Effect of carbon spacer length on the antibacterial properties of zwitterionic poly(sulfobetaine) type copolymeric brushes and their application in wound healing.

Creating infection resistant polymer brushes possessing antiadhesive, bactericidal and cell-compatible features can be regarded as a promising approach to prevent biomaterial-associated infections. In this work, polysulfobetaine type zwitterionic homo- and copolymer brushes with varying spacer lengths (charge separation distance between zwitterions, n = 3, 6 or 12) were allowed to grow onto a tartaric acid based aliphatic polyester substrate using surface initiated atom transfer radical polymerization. All of the brush modified surfaces were thoroughly characterized and assessed for their anti-infective performances in vitro. Strikingly, a suitable copolymer composition, i.e., polyZ6-co-Z12 (50/50 copolymer of polysulfobetaine methacrylates with 6 and 12 spacer lengths), was observed to inhibit bacterial growth completely and its activity was sustained for a long time (>3 months). Surprisingly, its antibacterial effect was found to be bactericidal, as is evident from live-dead staining of residual dead bacterial cells that can be easily released by exposing the surface to salt solution, thereby regenerating the surface. However, all of the other copolymer as well as homopolymer brushes exhibited bacteriostatic behavior. An attempt was made to understand the peculiar behavior of this particular brush composition. Nevertheless, the biocidal and also protein repellent brush did not display any cytotoxicity towards human cells, making it an ideal substrate to be used as an infection resistant biomedical implant. Animal studies further confirmed that this particular copolymeric brush modified scaffold can be a promising anti-infective wound dressing material with rapid wound healing effects as compared to the unmodified scaffold.

Encapsulation of zero valent iron nanoparticles in biodegradable amphiphilic janus particles for groundwater remediation.

Reactive Zero Valent Iron (ZVI) nanoparticles have been widely explored for in situ ground water remediation to degrade both non-aqueous phase liquid (NAPL) and water-soluble contaminants. However, they usually suffer from rapid oxidation and severe agglomerations restricting their delivery at NAPL/water interface. Aim of this study was to encapsulate the ZVI nanoparticles (50 nm) in amphiphilic bicompartmental Janus particles (711 ± 11 nm) fabricated by EHDC (electrohydrodynamic co-jetting). The dual compartments were composed of PLA (polylactic acid) and a blend of PLA, PE (poly (hexamethylene 2,3-O-isopropylidenetartarate) and PAG (photo acid generator). Upon UV irradiation, PAG releases acid to unmask hydroxyl groups present in PE to make only PE compartment hydrophilic. The entrapped ZVI nanoparticles (20 w/w%; ∼99 % encapsulation efficiency) were observed to degrade both hydrophilic (methyl orange dye) and hydrophobic (trichloro ethylene) contaminants. UV treated Janus particles provided stable dispersion (dispersed up to 3 weeks in water), prolonged reactivity (∼24 days in contaminated water), and recyclability (recyclable up to 9 times) as compared to non-treated ones. In addition, the amphiphilic Janus particles demonstrated high transportability (>95%) through porous media (sand column) with very low attachment efficiency (0.07), making them a promising candidate to target contaminants at NAPL/water interface prevailed in groundwater.

Advances in design of polymer brush functionalized inorganic nanomaterials and their applications in biomedical arena.

Grafting of polymer brush (assembly of polymer chains tethered to the substrate by one end) is emerging as one of the most viable approach to alter the surface of inorganic nanomaterials. Inorganic nanomaterials despite their intrinsic functional superiority, their applications remain restricted due to their incompatibility with organic or biological moieties vis-à-vis agglomeration issues. To overcome such a shortcoming, polymer brush modified surfaces of inorganic nanomaterials have lately proved to be of immense potential. For example, polymer brush-modified inorganic nanomaterials can act as efficient substrates/platforms in biomedical applications, ranging from drug-delivery to protein-array due to their integrated advantages such as amphiphilicity, stimuli responsiveness, enhanced biocompatibility, and so on. In this review, the current state of the art related to polymer brush-modified inorganic nanomaterials focusing, not only, on their synthetic strategies and applications in biomedical field but also the architectural influence of polymer brushes on the responsiveness properties of modified nanomaterials have comprehensively been discussed and its associated future perspective is also presented. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Photoinduced micropatterning on biodegradable aliphatic polyester surfaces for anchoring dual brushes and its application in bacteria and cell patterning.

In view of intrinsic challenges encountered in surface patterning on actual biomaterials such as the ones based on biodegradable polymers, we have demonstrated an innovative strategy to create micro-patterns on the surface of tartaric acid based aliphatic polyester P (poly(hexamethylene 2,3-O-isoprpylidentartarate)) without significant loss of its molecular weight. Around 10 wt% PAG (photoacid generator, 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine) was purposefully encapsulated in a polyester matrix comprising of P and PLA (polylactide) at a ratio of 5 : 95. With the help of a photomask, selective areas of the matrix were exposed to UV radiation at 395 nm for 25 min to trigger the acid release from PAG entrapped unmasked areas for generating hydroxyl functionality that was later converted to an ATRP (atom transfer radical polymerization) initiating moiety on the irradiated domain of P. In subsequent steps, spatio-selective surface modification by surface initiated ATRP was carried out to generate an alternate pattern of polyPEGMA (poly(ethylene glycol)methyl ether methacrylate) and polyDMAPS (poly(3-dimethyl-(methacryloyloxyethyl)ammonium propane sulfonate)) brushes on the matrix. The patterned surface modified with dual brushes was found to be antifouling in nature (rejection of >97% of proteins). Strikingly, an alternate pattern of live bacterial cells (E. coli and S. aureus) was evident and a relatively high population of bacteria was found on the polyPEGMA brush modified domain. However, a complete reverse pattern was visible in the case of L929 mouse fibroblast cells, i.e., cells were found to predominantly adhere to and proliferate on the zwitterionic brush modified surface. An attempt was made to discuss a plausible mechanism of selective cell adhesion on the zwitterionic brush domain. This novel strategy employed on the biodegradable polymer surface provides an easy and straightforward way to micro-pattern various cells, bacteria, etc. on biodegradable substrates which hold great potential to function as biochips, diagnostics, bacteria/cell microarrays, etc.

Designing suture-proof cell-attachable copolymer-mediated and curcumin- ß-cyclodextrin inclusion complex loaded aliphatic polyester-based electrospun antibacterial constructs.

The paper demonstrates curcumin/ß-cyclodextrin-based inclusion complex (IC) loaded polyvinyl alcohol (PVA) dip-coated and copolymer-compatibilized polylactic acid (PLA)/poly(ε-caprolactone) (PCL) blend-based electrospun mats (EMs) as antibacterial, and suture-resistant constructs, to overcome the present challenges in developing structurally-stable, biocompatible, pliable, and stand-alone multifunctional-biomedical-devices. The thermal, microstructural, and viscoelastic characterization confirmed the presence of H-bonding interactions between IC and PVA moieties and between IC incorporated PVA matrix with the copolymer-mediated nanotextured PLA/PCL blend-based EMs. IC release and surface PVA erosion induced a decrease in modulus (>4-fold) and strength (>2-fold) of constructs (post-release). Mechanistically new and architectural-framework-defined PVA-gelation induced bi-axially diverted suture-failure (post-release) and resulted in a significant enhancement in suture-retention-strength (>3-fold), energy (>5-fold), and displacement (>2-fold) for ~20 wt% IC-loaded-PVA-coated EM-constructs. The fabricated EM-constructs exhibited improvement in surface-hydrophilicity (contact angle ~45°), surface nano-roughness (~ 600 nm), surface area (~34 m2/g), pore volume (~3.6 × 10-2 cc/g), IC release efficacy (~20 % burst release), antibacterial activity (adherent bacteria <10 %) against E. coli and S. aureus, and L929 fibroblast-cell-viability (~135 %), which varied as a function of IC-content in the PVA matrix. Our study conceptually establishes a novel and efficient technique for designing antibacterial, suture-resistant engineered-EM-constructs with tunable properties for their potential use in wound-dressings, periodontal-membranes, drug-delivery, and regenerative-systems.

Dissipative particle dynamics simulation study on ATRP-brush modification of variably shaped surfaces and biopolymer adsorption.

We present a dissipative particle dynamics (DPD) simulation study on the surface modification of initiator embedded microparticles (MPs) of different shapes via atom transfer radical polymerization (ATRP) brush growth. The surface-initiated ATRP-brush growth leads to the formation of a more globular MP shape. We perform the comparative analysis of ATRP-brush growth on three different forms of particle surfaces: cup surface, spherical surface, and flat surface (rectangular/disk-shaped). First, we establish the chemical kinetics of the brush growth: the monomer conversion and the reaction rates. Next, we discuss the structural changes (shape-modification) of brush-modified surfaces by computing the radial distribution function, spatial density distribution, radius of gyration, hydrodynamic radius, and shape factor. The polymer brush-modified particles are well known as the carrier materials for enzyme immobilization. Finally, we study the biopolymer adsorption on ATRP-brush modified particles in a compatible solution. In particular, we explore the effect of ATRP-brush length, biopolymer chain length, and concentration on the adsorption process. Our results illustrate the enhanced biopolymer adsorption with increased brush length, initiator concentration, and biopolymer concentration. Most importantly, when adsorption reaches saturation, the flat surface loads more biopolymers than the other two surfaces. The experimental results verified the same, considering the disk-shaped flat surface particles, cup-shaped particles, and spherical particles.

Correction: Cytocompatible, soft and thick brush-modified scaffolds with prolonged antibacterial effect to mitigate wound infections.

Correction for 'Cytocompatible, soft and thick brush-modified scaffolds with prolonged antibacterial effect to mitigate wound infections' by Shaifali Dhingra et al., Biomater. Sci., 2022, 10, 3856-3877, https://doi.org/10.1039/d2bm00245k.

Cytocompatible, soft and thick brush-modified scaffolds with prolonged antibacterial effect to mitigate wound infections.

Biomedical device or implant-associated infections caused by pathogenic bacteria are a major clinical issue, and their prevention and/or treatment remains a challenging task. Infection-resistant antimicrobial coatings with impressive cytocompatibility offer a step towards addressing this problem. Herein, we report a new strategy for constructing highly antibacterial as well as cytocompatible mixed polymer brushes onto the surface of 3D printed scaffold made of biodegradable tartaric acid-based aliphatic polyester blends. The mixed brushes were nothing but a combination of poly(3-dimethyl-(methacryloyloxyethyl) ammonium propane sulfonate) (polyDMAPS) and poly((oligo ethylene glycol) methyl ether methacrylate) (polyPEGMA) with varying chain length (n) of the ethylene glycol unit (n = 1, 6, 11, and 21). Both homo and copolymeric brushes of polyDMAPS with polyPEGMA exhibited antibacterial efficacy against both Gram positive and Gram negative pathogens such as E. coli (Escherichia coli) and S. aureus (Staphylococcus aureus) because of the combined action of bacteriostatic effects originating from strongly hydrated layers present in zwitterionic (polyDMAPS) and hydrophilic (polyPEGMA) copolymer brushes. Interestingly, a mixed polymer brush comprising polyDMAPS and polyPEGMA (ethylene glycol chain unit of 21) at 50/50 ratio provided zero bacterial growth and almost 100% cytocompatibility (tested using L929 mouse fibroblast cells), making the brush-modified biodegradable substrate an excellent choice for an infection-resistant and cytocompatible surface. An attempt was made to understand their extraordinary performance with the help of contact angle, surface charge analysis and nanoindentation study, which revealed the formation of a hydrophilic, almost neutral, very soft surface (99.99% reduction in hardness and modulus) after modification with the mixed brushes. This may completely suppress bacterial adhesion. Animal studies demonstrated that these brush-modified scaffolds are biocompatible and can mitigate wound infections. Overall, this study shows that the fascinating combination of an infection-resistant and cytocompatible surface can be generated on biodegradable polymeric surfaces by modulating the surface hardness, flexibility and hydrophilicity by selecting appropriate functionality of the copolymeric brushes grafted onto them, making them ideal non-leaching, anti-infective, hemocompatible and cytocompatible coatings for biodegradable implants.

Compositionally Anisotropic Colloidal Surfactant Decorated with Dual Metallic Nanoparticles as a Pickering Emulsion Stabilizer and Their Application in Catalysis.

We aim to introduce compositionally anisotropic Janus particles, hemispheres of which was modified by hydrophilic poly(2-dimethyl amino ethyl methacrylate) [poly(DMAEMA)] brushes to display amphiphilic surfactant-type characteristics. Acquired by the electrohydrodynamic co-jetting technique, these colloidal surfactants were employed to stabilize octanol/water-based Pickering emulsion, which shows prolonged stability for more than 4 months. To explore their potential as the interfacial catalyst, iron(0) nanoparticles were incorporated in one hemisphere during electrojetting, whereas gold nanoparticles (GNPs) were patched onto the surface of the other hemisphere, which was previously modified by the poly(DMAEMA) brush. Ultimately, simultaneous rapid reduction (100% conversion in 1 min) of p-nitrophenol or methyl orange (MO) by GNPs in the aqueous phase and dechlorination of trichloroethylene (a hazardous chlorinated solvent waste) present in the octanol phase were accomplished at the organic-water interface stabilized by the Janus particles decorated by dual metallic nanoparticles. In addition, facile recovery and recyclability of the catalyst were also achieved. The novel colloidal surfactant demonstrated in this study may open up a new avenue to accomplish catalysis of several organic reactions occurring at the water-oil interface.

Infection Resistant Surface Coatings by Polymer Brushes: Strategies to Construct and Applications.

Bacteria-assisted infections on biomaterials used inside a body as an implant/device are one of the major threats to human health. Microbial-resistant coatings on biomaterials can potentially be considered to mitigate the biomaterial-associated infections. Usually biomaterials with leachable antimicrobial coatings, though economically attractive, provide only short-term protection of the surface against bacteria. Therefore, a stable, nonfouling or bactericidal, and biocompatible polymeric coating is highly desirable. In this regard, polymer brushes, defined as polymer chains tethered to a surface by one end, with suitable anti-infective functionality, represent a useful class of stable coatings which are covalently connected to the underlying surface, thus prolonging the infection resistance of the coated surface. Surface-initiated atom transfer radical polymerization (SI-ATRP) is a versatile technique for the generation of polymeric brushes via "grafting from" way. In this review, we have attempted to give a brief overview about the recent developments of surface coatings by infection-resistant polymer brushes synthesized via SI-ATRP and their applications in the biomedical field. On the basis of their charges, these anti-infective brushes can be classified into five different categories such as neutral, cationic, anionic, zwitterionic, and mixed brushes. The working mechanism of each type of brush in repelling (nonfouling/bacteriostatic) and/or killing (bactericidal) the bacteria has also been discussed. A brief summary of their future scope is also highlighted.

Protein Patterning on Microtextured Polymeric Nanobrush Templates Obtained by Nanosecond Fiber Laser.

Micropatterned polymer brushes have attracted attention in several biomedical areas, i.e., tissue engineering, protein microarray, biosensors, etc., for precise arrangement of biomolecules. Herein, a facile and scalable approach is reported to create microtextured polymer brushes with the ability to generate different type of protein patterns. Nanosecond fiber laser is exploited to generate micropatterns on poly(poly(ethylene glycol) methacrylate) (polyPEGMA) brush modified Ti alloy substrate. Surface initiated atom transfer radical polymerization is employed to grow PolyPEGMA brush (11-87 nm thick) on Ti alloy surface immobilized with initiator having an initiator density (σ*) of 1.5 initiators per nm2 . Polymer brushes are then selectively laser ablated and their presence on nontextured area is confirmed by atomic force microscopy, fluorescence microscopy, and X-ray photoelectron spectroscopy. Spatial orientation of biomolecules is first achieved by nonspecific protein adsorption on areas ablated by the laser, via physisorption. Further, patterned brushes of polyPEGMA are modified to activated ester that gives rise to protein conjugation specifically on nonlaser ablated brush areas. Moreover, the laser ablated brush modified patterned template is also successfully utilized for generating alternate patterns of bacteria. This promising technique can be further extended to create interesting patterns of several biomolecules which are of great interest to biomedical research community.

Recent advances in polymer scaffolds for biomedical applications.

The review provides insights into current advancements in electrospinning-assisted manufacturing for optimally designing biomedical devices for their prospective applications in tissue engineering, wound healing, drug delivery, sensing, and enzyme immobilization, and others. Further, the evolution of electrospinning-based hybrid biomedical devices using a combined approach of 3 D printing and/or film casting/molding, to design dimensionally stable membranes/micro-nanofibrous assemblies/patches/porous surfaces, etc. is reported. The influence of various electrospinning parameters, polymeric material, testing environment, and other allied factors on the morphological and physico-mechanical properties of electrospun (nano-/micro-fibrous) mats (EMs) and fibrous assemblies have been compiled and critically discussed. The spectrum of operational research and statistical approaches that are now being adopted for efficient optimization of electrospinning process parameters so as to obtain the desired response (physical and structural attributes) has prospectively been looked into. Further, the present review summarizes some current limitations and future perspectives for modeling architecturally novel hybrid 3 D/selectively textured structural assemblies, such as biocompatible, non-toxic, and bioresorbable mats/scaffolds/membranes/patches with apt mechanical stability, as biological substrates for various regenerative and non-regenerative therapeutic devices.

Advances in design and applications of polymer brush modified anisotropic particles.

Current advancements in the creation of anisotropy in particles and their surface modification with polymer brushes have established a new class of hybrid materials termed polymer brush modified anisotropic particles (PBMAP). PBMAPs display unique property combinations, e.g., multi-functionality in multiple directions along with smart behavior, which is not easily achievable in traditional hybrid materials. Typically, anisotropic particles can be categorized based on three different factors, such as shape anisotropy (geometry driven), compositional anisotropy (functionality driven), and surface anisotropy (spatio-selective surface modification driven). In this review, we have particularly focused on the synthetic strategies to construct the various type of PBMAPs based on inorganic or organic core which may or may not be isotropic in nature, and their applications in various fields ranging from drug delivery to catalysis. In addition, superior performances and fascinating properties of PBMAPs over their isotropic analogues are also highlighted. A brief overview of their future developments and associated challenges have been discussed at the end.

Agro-industrial-residues as potting media: physicochemical and biological characters and their influence on plant growth.

Nursery cultivation is recognized globally as an intensive production system to support quality seedlings as well as to manage resources efficiently. Apart from other factors, potting media (PM) play a crucial role in determining the success of nursery cultivation. Worldwide, peat is the most commonly used substrate in PM because of its favorable physicochemical properties. However, due to ascending environmental and ecological concerns regarding the use of peat, a variety of new substrates have been used/tested by researchers/practitioners/growers as PM. Bark, coir pith, wood fiber, compost derived from various agro-residues, and vermicompost either alone or in combination are some of the commonly explored substrates and found to have the potential to replace peat to a greater extent. In lieu of availability, abundance, low cost, and no/low processing requirement, the use of agro-industrial residue (AIR) in the PM is the current trend. However, challenges associated with their adoption cannot be ignored. The present review is focused on providing collective information, scientific knowledge and detailed analysis of various AIR used in PM. The critical evidence-based review would help in developing a consistent approach for the identification, selection and characterization of a new renewable substrate. In addition, it would help in developing a rationale understanding of the practical and economic realities involved in the adoption of the same in PM. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13399-021-01998-6.

From outbreak of COVID-19 to launching of vaccination drive: invigorating single-use plastics, mitigation strategies, and way forward.

The unforeseen outbreak of the COVID-19 epidemic has significantly stipulated the use of plastics to minimize the exposure and spread of the novel coronavirus. With the onset of the vaccination drive, the issue draws even more attention due to additional demand for vaccine packaging, transport, disposable syringes, and other allied devices scaling up to many million tonnes of plastic. Plastic materials in personal protective equipment (PPE), disposable pharmaceutical devices, and packaging for e-commerce facilities are perceived to be a lifesaver for the frontline healthcare personnel and the general public amidst recurring waves of the pandemic. However, the same material poses a threat as an evil environmental polluter when attributed to its indiscriminate and improper littering as well as mismanagement. The review not only highlights the environmental consequences due to the excessive use of disposable plastics amidst COVID-19 but also recommends mixed approaches to its management by adopting the combined and step-by-step methodology of adequate segregation, sterilization, sanitization activities, technological intervention, and process optimization measures. The overview finally concludes with some crucial way-forward measures and recommendations like the development of bioplastics and focusing on biodegradable/bio-compostable material alternatives to holistically deal with future pandemics.

Near-Infrared-II Semiconducting Polymer Dots for Deep-tissue Fluorescence Imaging.

Fluorescence imaging, particularly in the NIR-II region (1000-1700 nm), has become an unprecedented tool for deep-tissue in vivo imaging. Among the fluorescent nanoprobes, semiconducting polymer nanoparticles (Pdots) appear to be a promising agent because of their tunable optical and photophysical properties, ultrahigh brightness, minimal autofluorescence, narrow-size distribution, and low cytotoxicity. This review elucidates the recent advances in Pdots for deep-tissue fluorescence imaging and the facing future translation to clinical use.

Recent Developments in Semiconducting Polymer Dots for Analytical Detection and NIR-II Fluorescence Imaging.

In recent years, semiconducting polymer dots (Pdots) have attracted enormous attention in applications from fundamental analytical detection to advanced deep-tissue bioimaging due to their ultrahigh fluorescence brightness with excellent photostability and minimal cytotoxicity. Pdots have therefore been widely adopted for a variety types of molecular sensing for analytical detection. More importantly, the recent development of Pdots for use in the optical window between 1000 and 1700 nm, popularly known as the "second near-infrared window" (NIR-II), has emerged as a class of optical transparent imaging technology in the living body. The advantages of the NIR-II region over the traditional NIR-I (700-900 nm) window in fluorescence imaging originate from the reduced autofluorescence, minimal absorption and scattering of light, and improved penetration depths to yield high spatiotemporal images for biological tissues. Herein, we discuss and summarize the recent developments of Pdots employed for analytical detection and NIR-II fluorescence imaging. Starting with their preparation, the recent developments for targeting various analytes are then highlighted. After that, the importance of and latest progress in NIR-II fluorescence imaging using Pdots are reported. Finally, perspectives and challenges associated with the emergence of Pdots in different fields are given.