Photothermal-Responsive Conjugated Polymer Nanoparticles for Remote Control of Gene Expression in Living Cells

J-aggregates of multi-groups cyanine dye for NIR-IIa fluorescence-guided mild photothermal therapy under 1064 nm irradiation

NIR-IIa fluorescence imaging (FI) and NIR-II photothermal therapy (PTT) have gained popularity due to the advantages of high temporal and spatial resolution and deep penetration. However, the hyperthermia (>48 °C) of conventional PTT with nonspecific warming and thermal diffusion may inevitably cause damage to healthy tissues or organs surrounding the tumor. Therefore, it is highly desirable to provide effective cancer treatment by implementing mild photothermal therapy (mPTT) at mild temperatures with lower laser power density. Here, the nanotheranostic platform FN@P-GA NPs with NIR-II absorption and NIR-IIa emission was developed by constructing J-aggregates. FN@P-GA possesses good biocompatibility, favorable NIR-IIa FI performance, decent stability, and high photothermal conversion efficiency (57.6 %), which lays a solid foundation for FI-guided mPTT. Due to its ability to effectively down-regulate the expression of HSP90 and reduce cellular thermoresistance to kill cancer cells, FN@P-GA successfully achieved NIR-IIa FI-guided mPTT and demonstrated its potent anti-tumor effect under 1064 nm laser irradiation at mild temperature and low power density (0.3 W/cm2).

Polypeptide nanoparticles conjugated with an NIR-II organic dye for TRPV1 channel blockade enhance mild phototheranostics

Photothermal therapy (PTT) has attracted attention as a highly effective non-invasive treatment method. However, the high localized temperatures (>50 °C) required for its treatment will inevitably cause damage to the surrounding normal tissues. Therefore, it is important to develop novel and effective strategies to achieve mild photothermal therapy (mPTT). The overexpression of heat shock proteins (HSPs), a widespread heat stress protein, leads to the generation of heat resistance in cancer cells, which seriously affects the therapeutic effect. Thus, inhibiting the expression of HSPs to reduce the heat resistance of tumor cells is expected to enhance the therapeutic effect of mPTT. Here, we successfully synthesized a fluorescent probe bonded with an amphiphilic polypeptide to a cyanine dye and achieved physical encapsulation of the blocker SB705498 through a self-assembly process. SB705498 promotes transient receptor potential vanilloid member 1 (TRPV1) channel blockade that can inhibit the translocation of the heat shock transcription factor 1 (HSF 1) by blocking the influx of calcium and thus affecting the expression of HSPs, which has the potential to enhance the thermotherapy of cancer under mild conditions. In addition, the nanoparticles enabled NIR-II fluorescence imaging with good stability and high photothermal conversion efficiency (48.10 %). Therefore, this study provides a new strategy for realizing precise mPTT(<45 °C) guided by NIR-II imaging. STATEMENT OF SIGNIFICANCE: Inhibition of overexpression of heat shock proteins (HSPs) in cancer photothermal therapy (PTT) is expected to enhance the therapeutic effect of mild photothermal therapy (mPTT). In this study, we synthesized a fluorescent probe bonded to cyanine dyes with amphiphilic polypeptides and physically wrapped the blocker SB705498 through a self-assembly process. As a transient receptor potential vanillin 1 (TRPV1) channel blocker, SB705498 inhibits heat shock transcription factor 1 (HSF1) translocation by blocking calcium ion influx, thereby improving mPTT efficacy by inhibiting the expression of HSPs. The nanoparticles also enable NIR-II fluorescence imaging with good stability and high photothermal conversion efficiency (48.10 %). Thus, this study provides a new strategy for NIR-II mPTT.

Nano-optogenetics for Disease Therapies

Optogenetic, known as the method of 21 centuries, combines optic and genetic engineering to precisely control photosensitive proteins for manipulation of a broad range of cellular functions, such as flux of ions, protein oligomerization and dissociation, cellular intercommunication, and so on. In this technique, light is conventionally delivered to targeted cells through optical fibers or micro light-emitting diodes, always suffering from high invasiveness, wide-field illumination facula, strong absorption, and scattering by nontargeted endogenous substance. Light-transducing nanomaterials with advantages of high spatiotemporal resolution, abundant wireless-excitation manners, and easy functionalization for recognition of specific cells, recently have been widely explored in the field of optogenetics; however, there remain a few challenges to restrain its clinical applications. This review summarized recent progress on light-responsive genetically encoded proteins and the myriad of activation strategies by use of light-transducing nanomaterials and their disease-treatment applications, which is expected for sparking helpful thought to push forward its preclinical and translational uses.

Sensing, Imaging, and Therapeutic Strategies Endowing by Conjugate Polymers for Precision Medicine

Conjugated polymers (CPs) have promising applications in biomedical fields, such as disease monitoring, real-time imaging diagnosis, and disease treatment. As a promising luminescent material with tunable emission, high brightness and excellent stability, CPs are widely used as fluorescent probes in biological detection and imaging. Rational molecular design and structural optimization have broadened absorption/emission range of CPs, which are more conductive for disease diagnosis and precision therapy. This review provides a comprehensive overview of recent advances in the application of CPs, aiming to elucidate their structural and functional relationships. The fluorescence properties of CPs and the mechanism of detection signal amplification are first discussed, followed by an elucidation of their emerging applications in biological detection. Subsequently, CPs-based imaging systems and therapeutic strategies are illustrated systematically. Finally, recent advancements in utilizing CPs as electroactive materials for bioelectronic devices are also investigated. Moreover, the challenges and outlooks of CPs for precision medicine are discussed. Through this systematic review, it is hoped to highlight the frontier progress of CPs and promote new breakthroughs in fundamental research and clinical transformation.

Gene and Photothermal Combination Therapy: Principle, Materials, and Amplified Anticancer Intervention

Gene therapy (GT) and photothermal therapy (PTT) have emerged as promising alternatives to chemotherapy and radiotherapy for cancer treatment, offering noninvasiveness and reduced side effects. However, their efficacy as standalone treatments is limited. GT exhibits slow response rates, while PTT is confined to local tumor ablation. The convergence of GT and PTT, known as GT-PTT, facilitated by photothermal gene nanocarriers, has attracted considerable attention across various disciplines. In this integrated approach, GT reciprocates PTT by sensitizing cellular response to heat, while PTT benefits GT by improving gene translocation, unpacking, and expression. Consequently, this integration presents a unique opportunity for cancer therapy with rapid response and improved effectiveness. Extensive efforts over the past few years have been dedicated to the development of GT-PTT, resulting in notable achievements and rapid progress from the laboratory to potential clinical applications. This comprehensive review outlines recent advances in GT-PTT, including synergistic mechanisms, material systems, imaging-guided therapy, and anticancer applications. It also explores the challenges and future prospects in this nascent field. By presenting innovative ideas and insights into the implementation of GT-PTT for enhanced cancer therapy, this review aims to inspire further progress in this promising area of research.

Dual Activation of Calcium Channels Using Near-Infrared Responsive Conjugated Oligomer Nanoparticles for Precise Regulation of Blood Glucose Homeostasis

The rarity of efficient tools with spatiotemporal resolution and biocompatibility capabilities remains a major challenge for further progress and application of signaling manipulation. Herein, biomimetic conjugated oligomeric nanoparticles (CM-CONs) were developed to precisely modulate blood glucose homeostasis via the two-pronged activation of calcium channels. Under near-infrared (NIR) laser irradiation, CM-CONs efficiently generate local heat and reactive oxygen species (ROS), thereby simultaneously activating thermosensitive transient receptor potential V1 (TRPV1) and ROS-sensitive transient receptor potential A1 (TRPA1) calcium channels in small intestinal endocrine cells. The activation of the channels mediates inward calcium flow and then promotes glucagon-like peptide (GLP-1) secretion. Both in vitro and in vivo studies indicate that CM-CONs effectively regulate glucose homeostasis in diabetic model mice upon NIR light irradiation. This work develops a two-pronged attack strategy for accurately controlling blood glucose homeostasis, holding great prospects in the treatment for diabetes.

Ratiometric and visual determination of copper ions with fluorescent nanohybrids of semiconducting polymer nanoparticles and carbon dots

Developing nanohybrid composition based fluorescent carbon dots (CDs) for ratiometric detection of copper ions is highly appealing. Herein, a ratiometric sensing platform (GCDs@RSPN) for copper ions detection has been developed by loaded green fluorescence carbon dots (GCDs) on the surface of red emission semiconducting polymer nanoparticles (RSPN) through electrostatic adsorption. The GCDs, featuring abundant amino groups, can selectively bind copper ions to induce the photoinduced electron transfer, leading to fluorescence quenching. A good linearity within the range of 0-100 μM is obtained, and the limit of detection (LOD) is 0.577 μM by using obtained GCDs@RSPN as ratiometric probe to detect copper ion. Moreover, the paper-based sensor derived from GCDs@RSPN was successfully applied for the visual detection of Cu²⁺.

Applications of synthetic biology in medical and pharmaceutical fields

Synthetic biology aims to design or assemble existing bioparts or bio-components for useful bioproperties. During the past decades, progresses have been made to build delicate biocircuits, standardized biological building blocks and to develop various genomic/metabolic engineering tools and approaches. Medical and pharmaceutical demands have also pushed the development of synthetic biology, including integration of heterologous pathways into designer cells to efficiently produce medical agents, enhanced yields of natural products in cell growth media to equal or higher than that of the extracts from plants or fungi, constructions of novel genetic circuits for tumor targeting, controllable releases of therapeutic agents in response to specific biomarkers to fight diseases such as diabetes and cancers. Besides, new strategies are developed to treat complex immune diseases, infectious diseases and metabolic disorders that are hard to cure via traditional approaches. In general, synthetic biology brings new capabilities to medical and pharmaceutical researches. This review summarizes the timeline of synthetic biology developments, the past and present of synthetic biology for microbial productions of pharmaceutics, engineered cells equipped with synthetic DNA circuits for diagnosis and therapies, live and auto-assemblied biomaterials for medical treatments, cell-free synthetic biology in medical and pharmaceutical fields, and DNA engineering approaches with potentials for biomedical applications.

Highly Salt-Resistant interfacial solar evaporators based on Melamine@Silicone nanoparticles for stable Long-Term desalination and water harvesting

Interfacial solar-driven evaporation (ISE) is one of the most promising solutions for collecting fresh water, however, poor salt-resistance severely limits the long-term stability of solar evaporators. Here, highly salt-resistant solar evaporators for stable long-term desalination and water harvesting were fabricated by depositing silicone nanoparticles onto melamine sponge, and then modifying the hybrid sponge sequentially with polypyrrole and Au nanoparticles. The solar evaporators have a superhydrophilic hull for water transport and solar desalination, and a superhydrophobic nucleus for reducing heat loss. Spontaneous rapid salt exchange and reduction in salt concentration gradient were achieved due to ultrafast water transport and replenishment in the superhydrophilic hull with a hierachical micro-/nanostructure, which effectively prevents salt deposition during ISE. Consequently, the solar evaporators have long-term stable evaporation performance of 1.65 kg m^-2h^-1 for 3.5 wt% NaCl solution under 1 sun illumination. Moreover, 12.87 kg m^-2 fresh water was collected during consecutive 10 h ISE of 20 wt% brine under 1 sun without any salt precipitation. We believe that this strategy will shed a new light on the design of long-term stable solar evaporators for fresh water harvesting.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Stimuli-Responsive Gene Delivery Nanocarriers for Cancer Therapy

Gene therapy provides a promising approach in treating cancers with high efficacy and selectivity and few adverse effects. Currently, the development of functional vectors with safety and effectiveness is the intense focus for improving the delivery of nucleic acid drugs for gene therapy. For this purpose, stimuli-responsive nanocarriers displayed strong potential in improving the overall efficiencies of gene therapy and reducing adverse effects via effective protection, prolonged blood circulation, specific tumor accumulation, and controlled release profile of nucleic acid drugs. Besides, synergistic therapy could be achieved when combined with other therapeutic regimens. This review summarizes recent advances in various stimuli-responsive nanocarriers for gene delivery. Particularly, the nanocarriers responding to endogenous stimuli including pH, reactive oxygen species, glutathione, and enzyme, etc., and exogenous stimuli including light, thermo, ultrasound, magnetic field, etc., are introduced. Finally, the future challenges and prospects of stimuli-responsive gene delivery nanocarriers toward potential clinical translation are well discussed. The major objective of this review is to present the biomedical potential of stimuli-responsive gene delivery nanocarriers for cancer therapy and provide guidance for developing novel nanoplatforms that are clinically applicable.

Engineered Phage with Aggregation-Induced Emission Photosensitizer in Cocktail Therapy against Sepsis

Sepsis, a widely recognized disease, is characterized by multiple pathogen infections. Therefore, it is imperative to develop methods that can efficiently identify and neutralize pathogen species. Phage cocktail therapy utilizes the host specificity of phages to adapt to infect resistant bacteria. However, its low sterilization stability efficiency and lack of imaging units seriously restrict its application. Here, a novel strategy combining the aggregation-induced emission photosensitizer (AIE-PS) TBTCP-PMB with phages through a nucleophilic substitution reaction between benzyl bromide and sulfhydryl groups to remove pathogenic bacteria for sepsis treatment is proposed. This strategy retains the phage's host specificity while possessing AIE-PS characteristics with a fluorescence imaging function and reactive oxygen species (ROS) for detecting and sterilizing bacteria. This synergetic strategy combining phage cocktail therapy and photodynamic therapy (PDT) shows a strong "1 + 1 > 2" bactericidal efficacy and superior performance in sepsis mouse models with good biocompatibility. Furthermore, the strategy can quickly diagnose blood infections of clinical blood samples. This simple and accurate strategy provides a promising therapeutic platform for rapid pathogen detection and point-of-care diagnosis. Moreover, it presents a new method for expanding the library of antibacterial drugs to develop new strain identification and improve infectious disease treatment, thereby demonstrating strong translational potential.

Lanthanide-Doped Upconversion Nanoparticles: Exploring A Treasure Trove of NIR-Mediated Emerging Applications

Lanthanide-doped upconversion nanoparticles (UCNPs) possess the remarkable ability to convert multiple near-infrared (NIR) photons into higher energy ultraviolet-visible (UV-vis) photons, making them a prime candidate for several advanced applications within the realm of nanotechnology. Compared to traditional organic fluorophores and quantum dots (QDs), UCNPs possess narrower emission bands (fwhm of 10-50 nm), large anti-Stokes shifts, low toxicity, high chemical stability, and resistance to photobleaching and blinking. In addition, unlike UV-vis excitation, NIR excitation is nondestructive at lower power intensities and has high tissue penetration depths (up to 2 mm) with low autofluorescence and scattering. Together, these properties make UCNPs exceedingly favored for advanced bioanalytical and theranostic applications, where these systems have been well-explored. UCNPs are also well-suited for bioimaging, optically modulating chemistries, forensic science, and other state-of-the-art research applications. In this review, an up-to-date account of emerging applications in UCNP research, beyond bioanalytical and theranostics, are presented including optogenetics, super-resolution imaging, encoded barcodes, fingerprinting, NIR vision, UCNP-assisted photochemical manipulations, optical tweezers, 3D printing, lasing, NIR-II imaging, UCNP-molecule nanohybrids, and UCNP-based persistent luminescent nanocrystals.

A Strategy of On-Demand Immune Activation for Antifungal Treatment Using Near-Infrared Responsive Conjugated Polymer Nanoparticles

Pathogenic fungal infection is a major clinical threat because pathogenic fungi have developed resistant mechanisms to evade the innate immune response, especially interactions with macrophages. Herein, a strategy to activate immune responses of macrophages to fungi based on near-infrared (NIR) responsive conjugated polymer nanoparticles (CPNs-M) is reported for antifungal immunotherapy. Under NIR light irradiation, CPNs-M exposes β-glucan on the surface of fungal conidia by photothermal damage and drug released from CPNs-M. The exposed β-glucan elicits macrophage recognition and subsequently activates calcium-calmodulin (Ca²⁺-CaM) signaling followed by the LC3-associated phagocytosis (LAP) pathway to kill fungal conidia. Consequently, a remarkable elimination of intracellular fugal conidia and successful treatment of fungal pneumonia are achieved. This remote regulation strategy to restore pathogen-immune cell interaction on demand provides a new insight into combatting intractable intracellular infections.

Soft nano and microstructures for the photomodulation of cellular signaling and behavior

Photoresponsive soft materials are everywhere in the nature, from human's retina tissues to plants, and have been the inspiration for engineers in the development of modern biomedical materials. Light as an external stimulus is particularly attractive because it is relatively cheap, noninvasive to superficial biological tissues, can be delivered contactless and offers high spatiotemporal control. In the biomedical field, soft materials that respond to long wavelength or that incorporate a photon upconversion mechanism are desired to overcome the limited UV-visible light penetration into biological tissues. Upon light exposure, photosensitive soft materials respond through mechanisms of isomerization, crosslinking or cleavage, hyperthermia, photoreactions, electrical current generation, among others. In this review, we discuss the most recent applications of photosensitive soft materials in the modulation of cellular behavior, for tissue engineering and regenerative medicine, in drug delivery and for phototherapies.

Bright Near-Infrared π-Conjugated Oligomer Nanoparticles for Deep-Brain Three-Photon Microscopy Excited at the 1700 nm Window in Vivo

The development of three-photon fluorophores with 1700 nm excitation is pressingly desirable for in vivo imaging of tissue resided deep inside the brain. Herein, we report a designed and synthesized fluorescent molecule (OFET) for in vivo mouse brain imaging with three-photon microscopy at a record imaging depth. The OFET molecule has a relatively high fluorescence brightness and has a near-infrared (NIR) maximum emission at 820 nm after integrating as water-dispersible nanoparticles (OEFT NPs). Under 1720 nm excitation, OFET NPs show a large three-photon action cross-section of 1.06 × 10^-82 cm⁶ s²/photon², which is more than twice that of the commonly used sulforhodamine 101 (SR101) dye. Benefiting from the high tissue penetration depths for both the long excitation in the second NIR window of 1720 nm and the emission wavelength in the first NIR window of 820 nm, a high brightness, and a large action cross-section of three-photon, OFET NPs have good deep-brain imaging performance. Brain vasculatures of a mouse located at a depth of 1696 μm can be clearly resolved in vivo. With no observable cytotoxicity even in a high concentration, the present OFET NPs suggest that fluorescent π-conjugated oligomers are of great potential in high-resolution 3PM imaging of in vivo deep-tissue.

Near-Infrared Light-Responsive Nanoinhibitors for Tumor Suppression through Targeting and Regulating Anion Channels

The gated state of anion channels is involved in the regulation of proliferation and migration of tumors. Specific regulators are urgently needed for efficacious cancer ablation. For this purpose, it is essential to understand the molecular mechanisms of interaction between the regulators and anion channels and apply this knowledge to regulate anion channels. Transmembrane 16A (TMEM16A) is the molecular basis of the calcium-activated chloride channels. It is an anion channel activated by Ca²⁺, and the inhibition of TMEM16A is associated with a decrease in tumorigenesis. Herein, we characterized a natural compound procyanidin (PC) as an efficacious and selective inhibitor of TMEM16A with an IC₅₀ of 10.6 ± 0.6 μM. Our research revealed the precise sites (D383, R535, and E624) of electrostatic interactions between PC and TMEM16A. Near-infrared (NIR)-light-responsive photothermal conjugated polymer nanoparticles encapsulating PC (CPNs-PC) were established to remotely target and regulate the TMEM16A anion channel. Upon NIR irradiation, CPNs-PC downregulated the signaling pathway downstream of TMEM16A and arrested the cell cycle progression of cancer cells and improved the bioavailability of PC. The tumor inhibition ratio of CPNs-PC was superior to PC by 13.4%. Our findings enabled the development of a strategy to accurately and remotely regulate anion channels to promote tumor regression using NIR-light-responsive conjugated polymer nanoparticles containing specific inhibitors of TMEM16A.

Polymer Nanoparticles Overcome Drug Resistance by a Dual-Targeting Apoptotic Signaling Pathway in Breast Cancer

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) activating therapy has received wide attention due to its capacity to precisely induce cancer cell apoptosis. However, drug resistance and the poor pharmacokinetic properties of TRAIL protein are obstacles in TRAIL-based therapy for cancer. Herein, a strategy is developed to remotely control and specifically initiate TRAIL-mediated apoptotic signaling to promote TRAIL-resistant cancer cell apoptosis using near-infrared (NIR) light-absorbing conjugated polymer nanoparticles (CPNs). Upon 808 nm laser excitation, the promoter 70 kilodalton heat shock protein (HSP70) initiates transcription of the TRAIL gene in response to heat shock, thereby expressing TRAIL protein in breast cancer cells, which activates the TRAIL-mediated apoptosis signaling pathway. Simultaneously, the CPNs locally release W-7, which targets calmodulin (CaM) and further promotes caspase-8 cleavage and enhances cancer cell apoptosis. Both in vitro and in vivo results demonstrate that CPNs/W-7/pTRAIL produces an excellent synergistic therapeutic effect on breast cancer upon near-infrared light with low toxicity. Therefore, this work provides a strategy for overcoming drug resistance through dual-targeting TRAIL-mediated apoptotic signaling in breast cancer.

An Enhanced Photothermal Therapeutic Iridium Hybrid Platform Reversing the Tumor Hypoxic Microenvironment

As hypoxia is closely associated with tumor progression, proliferation, invasion, metastasis, and strong resistance to therapy, regulating and overcoming the hypoxia tumor microenvironment are two increasingly important aspects of tumor treatment. Herein, we report a phototherapeutic platform that uses the organic photosensitizer diketopyrrolopyrrole (DPP) derivative and inorganic iridium salts (IrCl₃) with photothermal activity and the capacity to decompose H₂O₂ efficiently. The characterization of their photophysical properties proved that DPP-Ir nanoparticles are capable of remarkable near-infrared (NIR) absorption, and compared to DPP nanoparticles, the photothermal conversion efficiency (PCE) increases from 42.1% in DPP nanoparticles to 67.0% in DPP-Ir nanoparticles. The hybrid nanoparticles utilize the catalytic decomposition of endogenous H₂O₂ to produce oxygen for the downregulation of the hypoxia-inducible factor 1 subunit alpha (HIF-1α) protein, which could reverse the tumor hypoxic microenvironment. Benefiting from the excellent optical properties and good biocompatibility, the hybrid platform exhibits efficient photothermal therapeutic effects as well as good biological safety. In conclusion, such a hybrid platform could improve photothermal therapy against cancer.

Photothermal Conjugated Polymer Nanoparticles for Suppressing Breast Tumor Growth by Regulating TRPA1 Ion Channels

Cancer cells survive by relying on oxidative stress defense against the accumulation of reactive oxygen species (ROS) during tumor formation. ROS-sensitive TRPA1 ion channels are overexpressed in breast cancer cells and induce a large influx of Ca²⁺ which upregulates the anti-apoptotic pathway to lead breast cancer cells to produce oxidative stress defense and enhance the resistance to ROS related chemotherapy. Targeting and inhibiting the TRPA1 ion channels are critical for breaking down the oxidative stress defense system and overcoming cellular resistance. Here, near-infrared (NIR) light-responsive conjugated polymer nanoparticles are designed and prepared to promote apoptosis of breast cancer cells, reduce cell drug resistance and suppress tumor growth through the remote and precise regulation of TRPA1 ion channels. Upon 808 nm laser irradiation, the nanoparticles block the formation of Ca²⁺ /CaM complex and regulate the content of MCL-1 protein. Especially, the nanoparticles overcome drug resistance of cancer cells, therefore accelerating apoptosis of cancer cells and suppressing tumor growth in mice. Compared with carboplatin, the volume of tumor induced by NPs-H decreases by 54.1%. This work provides a strategy to disrupt the oxidative stress defense system and downregulate the antiapoptotic signaling pathway in cancer cells.

Conjugated polymer nanoparticles and their nanohybrids as smart photoluminescent and photoresponsive material for biosensing, imaging, and theranostics

The emergence of conjugated polymers (CPs) has provided a pathway to attain smart multifunctional conjugated polymer nanoparticles (CPNs) with enhanced properties and diverse applications. CPNs based on π-extended CPs exhibit high fluorescence brightness, low cytotoxicity, excellent photostability, reactive oxygen species (ROS) generation ability, high photothermal conversion efficiency (PCE), etc. which endorse them as an excellent theranostic tool. Furthermore, the unique light-harvesting and energy transfer properties of CPNs enables their transformation into smart functional nanohybrids with augmented performance. Owing to such numerous features, simple preparation method and an easy separation process, the CPNs and their hybrids have been constantly rising as a frontrunner in the domain of medicine and much work has been done in the respective research area. This review summarizes the recent progress that has been made in the field of CPNs for biological and biomedical applications with special emphasis on biosensing, imaging, and theranostics. Following an introduction into the field, a first large section provides overview of the conventional as well as recently established synthetic methods for various types of CPNs. Then, the CPNs-based fluorometric assays for biomolecules based on different detection strategies have been described. Later on, examples of CPNs-based probes for imaging, both in vitro and in vivo using cancer cells and animal models have been explored. The next section highlighted the vital theranostic applications of CPNs and corresponding nanohybrids, mainly via imaging-guided photodynamic therapy (PDT), photothermal therapy (PTT) and drug delivery. The last section summarizes the current challenges and gives an outlook on the potential future trends on CPNs as advanced healthcare material.

Egr1/HSP70 Promoter-Driven Activation of Gene Expression for Synergistic Anti-Hepatoma Using PEI-MZF Nanoparticles and Radiation

INTRODUCTION

Spatially restricted gene expression circumvents the gene expression and gene vector problem by enabling localized amplification. The objective of this study is to construct a spatially restricted gene expression for liver cancer therapy based upon the MFH-absorbing properties of PEI- Mn0.5zn0.5Fe2o4, gene therapy and radiation.

METHODS

Mn0.5zn0.5Fe2O4 (MZF) magnetic nanoparticles were prepared by an improved chemical co-precipitation method, modified by polyethylene imine (PEI), and then the structure, modification characters, biocompatibility, temperature rise and control ability and binding efficiency of the plasmid were characterized. Then, the dual-promoter plasmid PCDNA3.1-EGR1-HSP70-HSVTK was constructed. The recombinant vectors were identified by enzyme digestion analysis and DNA sequencing. The TK gene expression level was detected by realtime-PCR assay in HEK293 cells. Also, the HSV-TK gene expression was detected in SMMC7721 cells with the help of PEI-Mn0.5Zn0.5Fe2O4. In vitro anti-tumor experiment, MTT assay and flow cytometry were used to evaluate the therapeutic effects of the cultured SMMC7721 cells treated by different ways. In vivo anti-tumor experiment, the xenografted mice were treated by different ways for three times to detect the antitumor effect.

RESULTS

The Mn0.5Zn0.5Fe2O4 magnetic nanoparticles could be successfully prepared through improved co-precipitation process and showed good biocompatibility. And PEI had been coated on MZF complex. The modified PEI-MZF presented favorable dispensability, responsibility to magnetism, good loading capability and transfect capability. Also, pCDNA3.1-Egr1-Hsp70-HSVTK plasmid had been constructed successfully and could be induced by heat and irradiation. It would be used for further target gene therapy research. The antitumor results in vitro showed: The therapeutic effects of nanosized PEI-MZF-HSV-TK complex could significantly inhibit the proliferation of cultured liver cancer cells (SMC7721), induce cell apoptosis and had a prominent cell cycle disturbance in the S phase in vitro. The results in vivo showed: The combined therapy induced by PEI-MZF-HSV-TK could inhabit the growth of hepatocellular carcinoma xenografts by killing and inhabiting the proliferation of the tumor cells.

CONCLUSION

The novel site-directed heat/radiation-inducible expression system based upon the hyperthermia (by MFH) and radiation possessed superior antitumor effect in vivo and in vitro.

Scalable Fabrication of Conjugated Microporous Polymer Sponges for Efficient Solar Steam Generation

Seawater evaporation realized by solar-thermal conversion represents one of the most sustainable and effective strategies to obtain fresh water. Many approaches have been proposed to achieve high efficiencies of solar-thermal conversion, but their practical applications are limited by the low scalability. Herein, novel porphyrin/aniline-based conjugated microporous polymers (PACMPs) are synthesized via a Buchwald-Hartwig coupling reaction, which are then integrated with polyurethane sponges via a simple dip-coating technique. The PACMP-modified sponges (PACSs) retain the high porosity of the sponge substrate and excellent solar-thermal conversion properties of PACMPs. Under standard solar irradiation (1 kW m^-2), PACSs achieve a high seawater evaporation rate of 1.31 kg m^-2 h^-1 with a solar-thermal conversion efficiency of 86.3%. PACSs show no salt accumulation and high performance of desalination and dye decolorization, removing >99.9% salt and >99.2% dye, respectively. The self-floating characteristic, recyclability, and durable solar-thermal evaporation efficiencies enable PACSs to be promising candidate materials for seawater desalination and sewage purification.

Light manipulation for fabrication of hydrogels and their biological applications

The development of biocompatible materials with desired functions is essential for tissue engineering and biomedical applications. Hydrogels prepared from these materials represent an important class of soft matter for mimicking extracellular environments. In particular, dynamic hydrogels with responsiveness to environments are quite appealing because they can match the dynamics of biological processes. Among the external stimuli that can trigger responsive hydrogels, light is considered as a clean stimulus with high spatiotemporal resolution, complete bioorthogonality, and fine tunability regarding its wavelength and intensity. Therefore, photoresponsiveness has been broadly encoded in hydrogels for biological applications. Moreover, light can be used to initiate gelation during the fabrication of biocompatible hydrogels. Here, we present a critical review of light manipulation tools for the fabrication of hydrogels and for the regulation of physicochemical properties and functions of photoresponsive hydrogels. The materials, photo-initiated chemical reactions, and new prospects for light-induced gelation are introduced in the former part, while mechanisms to render hydrogels photoresponsive and their biological applications are discussed in the latter part. Subsequently, the challenges and potential research directions in this area are discussed, followed by a brief conclusion. STATEMENT OF SIGNIFICANCE: Hydrogels play a vital role in the field of biomaterials owing to their water retention ability and biocompatibility. However, static hydrogels cannot meet the dynamic requirements of the biomedical field. As a stimulus with high spatiotemporal resolution, light is an ideal tool for both the fabrication and operation of hydrogels. In this review, light-induced hydrogelation and photoresponsive hydrogels are discussed in detail, and new prospects and emerging biological applications are described. To inspire more research studies in this promising area, the challenges and possible solutions are also presented.

Conjugated Polymers for Biomedical Applications

Conjugated polymers (CPs) are a series of organic semiconductor materials with large π-conjugated backbones and delocalized electronic structures. Due to their specific photophysical properties and photoelectric effects, plenty of CPs...

Covalent organic framework based nanoagent for enhanced mild-temperature photothermal therapy

Photothermal therapy effectively ablates tumors by hyperthermia (>50 °C) under laser irradiation. However, the hyperthermia may inevitably diffuse to the surrounding healthy tissues to induce additional damage. Thus, effective cancer therapy by mild photothermal therapy at low temperatures is greatly desirable. In this study, a nanoagent (COF-GA) was designed to inhibit HSP90 for enhanced photothermal therapy against cancer at low temperatures. The nanoscale covalent organic frameworks (COFs) were able to increase the temperature of the tumor tissue under laser irradiation, which can transfer the energy of laser into heat for cancer cell killing. Gambogic acid (GA), as an inhibitor of HSP90, was used to overcome the heat resistance of tumor, achieving efficient mild-temperature photothermal therapy. As an excellent candidate for the photothermal therapy agent, COF-GA can induce the temperature to elevate as the exposure time increased when irradiated with laser. In vivo tests further demonstrated that the tumor growth was able to be significantly suppressed after being treated with COF-GA. The mild-temperature photothermal therapy exhibits an excellent antitumor efficacy at a relatively low temperature and minimizes the nonspecific thermal damage to normal tissues. This COF-GA nanoagent also enriches our understanding towards the various applications of COFs, particularly in the biomedicine field.

Conjugated Polymers: Optical Toolbox for Bioimaging and Cancer Therapy

Conjugated polymers (CPs) are capable of coordinating the electron coupling phenomenon to bestow powerful optoelectronic features. The light-harvesting and light-amplifying properties of CPs are extensively used in figuring out the biomedical issues with special emphasis on accurate diagnosis, effective treatment, and precise theranostics. This review summarizes the recent progress of CP materials in bioimaging, cancer therapeutics, and introduces the design strategies by rationally tuning the optical properties. The recent advances of CPs in bioimaging applications are first summarized and the challenges to clear the future directions of CPs in the respective area are discussed. In the following sections, the focus is on the burgeoning applications of CPs in phototherapy of the tumor, and illustrates the underlying photo-transforming mechanism for further molecular designing. Besides, the recent progress in the CPs-assistant drug therapy, mainly including drug delivery, gene therapeutic, the optical-activated reversion of tumor resistance, and synergistic therapy has also been discussed elaborately. In the end, the potential challenges and future developments of CPs on cancer diagnosis and therapy are also illuminated for the improvement of optical functionalization and the promotion of clinical translation.

Self-assembled micelle responsive to quick NIR light irradiation for fast drug release and highly efficient cancer therapy

Upconversion nanoparticles (UCNPs) have been used for designing near infrared (NIR) light-responsive nanocarriers and controllable drug release. However, the need for long-term NIR light irradiation over hours impaired their application efficiency. Here we develop a self-assembled micelle of amphipathic polymer P-DASA which degrades via quick NIR light irradiation. UCNPs and DOX are also encapsulated in the micelle for quick drug release. P-DASA is composed of hydrophilic polyethylene glycol segment and photo-responsive hydrophobic donor-acceptor Stenhouse adduct (DASA). Only 5-min NIR irradiation causes the hydrophilicity conversion of P-DASA and the complete disruption of micelle with DOX fast release of 83.7% in 30 min to achieve highly efficient therapy. Moreover, the P-glycoprotein mediated DOX efflux is also diminished by concomitantly producing NO intracellularly. This micelle demonstrates impressive in vivo therapeutic effect, and thus provides an avenue for highly efficient cancer therapy.

Near-Infrared-Light Remote-Controlled Activation of Cancer Immunotherapy Using Photothermal Conjugated Polymer Nanoparticles

Remote control of the therapeutic process is an ideal strategy for maximizing efficacy and avoiding side effects, especially for cancer immunotherapy. Herein, a conjugated polymer nanoparticles (CPNs)-mediated optogenetic system for in situ activation of immunotherapy under near-infrared laser irradiation is reported. This system is composed of photothermal CPNs and interferon-gamma (IFN-γ) plasmid driven by heat shock promoter HSP70. The photothermally responsive CPNs serve as a photo-heat nanotransducer to trigger the gene transcription of IFN-γ cytokine. The secreted IFN-γ from cancer cells can sufficiently elicit surrounding tumor-associated macrophages activation through IFN-γ-JAK-STAT1 transcription-factor signaling pathway and finally induce cancer cell killing by immunotherapy. Therefore, this synergetic optogenetic system provides a promising approach to remotely control the process of cancer immunotherapy.

Reusable Fluorescent Nanobiosensor Integrated in a Multiwell Plate for Screening and Quantification of Antidiabetic Drugs

A highly stable and reusable fluorescent multisample nanobiosensor for the detection of α-glucosidase inhibitors has been developed by coupling fluorescent liposomal nanoparticles based on conjugated polymers (L-CPNs) to the enzyme α-glucosidase, one of the main target enzymes in the treatment of type 2 diabetes. The mechanism of sensing is based on the fluorescence "turn-on" of L-CPNs by p-nitrophenol (PNP), the end product of the enzymatic hydrolysis of p-nitrophenyl-α-d-glucopyranoside. L-CPNs, composed of lipid vesicles coated with a blue-emitting cationic polyfluorene, were designed and characterized to obtain a good response to PNP. Two nanobiosensor configurations were developed in this study. In the first step, a single-sample nanobiosensor composed of L-CPNs and α-glucosidase entrapped in a sol-gel glass was developed in order to characterize and optimize the device. In the second part, the nanobiosensor was integrated and adapted to a multiwell microplate and the possibility of reusing it and performing multiple measurements simultaneously with samples containing different α-glucosidase inhibitors was investigated. Using super-resolution confocal microscopy, L-CPNs could be visualized within the sol-gel matrix, and the quenching of their fluorescence, induced by the substrate, was directly observed in situ. The device was also shown to be useful not only as a platform for screening of antidiabetic drugs but also for quantifying their presence. The latter application was successfully tested with the currently available drug, acarbose.

NIR-II Absorbing Semiconducting Polymer-Triggered Gene-Directed Enzyme Prodrug Therapy for Cancer Treatment

Exploration of facile strategies for precise regulation of target gene expression remains highly challenging in the development of gene therapies. Especially, a stimuli-responsive nanocarrier integrated with ability of noninvasive remote control for treating wide types of cancers is rarely developed. Herein, a NIR-II absorbing semiconducting polymer (PBDTQ) is employed to remotely activate the heat-inducible heat-shock protein 70 (HSP70) promoter under laser irradiation, further realizing regulation of gene-directed enzyme prodrug therapy (GDEPT) for cancer treatment in mild hyperthermia. In this multifunctional nanocomposite, the PBDTQ and double suicide gene plasmid (pSG) based on HSP70 promoter are incorporated into a lipid complex. Upon NIR-II laser excitation, the mild photothermal effect (≈43 °C) generated from PBDTQ can cause the release of pSG and activation of HSP70 promoter, and then upregulate suicide gene expression triggered by the HSP70 promoter which can further convert the nontoxic prodrug into its cytotoxic metabolites. Therefore, this work demonstrates a universal NIR-II laser-triggered GDEPT using semiconducting polymers as the photothermal generator for cancer treatment with minimized collateral damage and nontargeted side effects.

A mesoporous polydopamine nanoparticle enables highly efficient manganese encapsulation for enhanced MRI-guided photothermal therapy

Theranostic agents based on magnetic resonance imaging (MRI) and photothermal therapy (PTT) play an important role in tumor therapy. However, the available theranostic agents are facing great challenges such as biocompatibility, MRI contrast effect and photothermal conversion efficiency (η). In this work, mesoporous polydopamine nanoparticles (MPDAPs/Mn) were prepared on MRI and PTT combined theranostic nanoplatforms, of which the high loading manganese ions and specific surface areas enable good MRI contrast and excellent photothermal conversion efficiency, respectively. The MPDAPs/Mn have uniform morphology, good stability and biocompatibility. Meanwhile, in vitro and in vivo studies have confirmed their superior T₁-weighted MRI effect and photothermal conversion efficiency. Furthermore, MPDAPs/Mn have excellent antitumor efficacy in HeLa tumor-bearing mice. Therefore, this developed MPDAPs/Mn theranostic nanoplatform could be a promising candidate for MRI-guided photothermal cancer therapy.

Molecular engineering of diketopyrrolopyrrole-conjugated polymer nanoparticles by chalcogenide variation for photoacoustic imaging guided photothermal therapy

Photothermal therapy is promising for augmenting cancer therapeutic outcomes in cancer treatment. Diketopyrrolopyrrole (DPP)-conjugated polymer nanoparticles are in focus due to their dual photoacoustic imaging and photothermal therapy functions. Herein, the design and synthesis of three near-infrared absorbing conjugated polymers, named DPP-SO, DPP-SS and DPP-SSe, with heteroatom substitution of the thiophene moiety were developed for a photoacoustic imaging guided photothermal therapy. It was demonstrated that systematically changing only the heteroatom from O to S or Se could apparently adjust the absorption spectrum and energy gap of DPP-conjugated polymers to obtain the most suitable photothermal transduction agents (PTAs) for use in biomedicine. The characterization of photophysical properties proved that the photothermal conversion efficiency and absorption coefficient of DPP-SO nanoparticles under 808 nm irradiation was up to 79.3% and 66.51 L g^-1 cm^-1, respectively, which were much higher than those of DPP-SS and DPP-SSe nanoparticles. Remarkably, the IC₅₀ value of DPP-SO for killing A549 cells was half that of DPP-SS and DPP-SSe nanoparticles. Further in vivo works demonstrated efficient photothermal therapeutic effects of DPP-SO nanoparticles with the guidance of photoacoustic imaging. Thus, this is an efficient method to regulate the photothermal performance of DPP-conjugated polymers by changing the heteroatom in the molecular skeleton.

ROS-Responsive and active targeted drug delivery based on conjugated polymer nanoparticles for synergistic chemo-/photodynamic therapy

Stimuli-responsive and active targeted drug release is highly significant and challenging for precise and effective cancer therapy. Herein, a reactive oxygen species (ROS)-responsive drug delivery system iRGD-BDOX@CPNs with active targeting for chemo-/photodynamic (PDT) synergistic therapy has been reported. This nanocarrier iRGD-BDOX@CPNs is constructed by the self-assembly of conjugated polymer poly(fluorene-co-vinylene) (PFV), prodrug BDOX (doxorubicin modified with a phenylboronic acid ester group) and an amphiphilic polymer (DSPE-PEG) modified with internalized RGD (DSPE-PEG-iRGD). The hydrophobic inner cores formed by PFV main chains tightly enclose BDOX. Due to PFV generating many ROS by light triggering, the BDOX prodrug can be in situ activated, resulting in the highly efficient drug release. In addition, the remarkable fluorescence recovery could be used for real-time monitoring of drug delivery and guiding antitumor therapy. Contributing to the specific recognition between iRGD and integrin αvβ3 receptors over-expressed on the surface of tumor cells, the active targeting and uptake of iRGD-BDOX@CPNs in tumor cells are greatly enhanced. The prominent anti-cancer effect of iRGD-BDOX@CPNs is realized by targeted drug delivery and synergistic therapeutic effects of PDT/chemotherapy. This study illustrates that the development of ROS-responsive and targeted drug delivery nanocarriers iRGD-BDOX@CPNs provides a new insight for controllable drug release and tumor precision therapy.

On-Demand Antimicrobial Agent Release from Functionalized Conjugated Oligomer-Hyaluronic Acid Nanoparticles for Tackling Antimicrobial Resistance

Controllable drug release is promising for fighting against antimicrobial resistance, which is a critical threat to human health worldwide. Herein, new hyaluronidase-responsive conjugated oligo(thiophene ethynylene) (OTE)-covalently modified hyaluronic acid (OTE-HA) nanoparticles for on-demand release of antimicrobial agents are reported. The synthesis of amphiphilic OTE-HA was carried out by esterification reaction. The resulting macromolecules were self-assembled in water to form nanoparticles, in which the hydrophobic OTE section, as bactericides, formed "cores" and the hydrophilic hyaluronic acid (HA) formed "shells". The OTE-HA nanoparticles avoid bactericide premature leakage and effectively block the dark cytotoxicity of the OTE section, possessing excellent biocompatibility. Using methicillin-resistant Staphylococcus aureus (MRSA) as an example, hyaluronidase, largely secreted by MRSA, can in situ trigger the release of OTE via hydrolyzing OTE-HA nanoparticles into fragments, even disaccharides linked with OTE. Importantly, the OTE section could effectively break cell membranes, leading to bacterial death. The half-maximal inhibitory concentration of the nanoparticles against MRSA is 3.3 μg/mL. The great antibacterial activity of OTE-HA nanoparticles against Gram-positive bacteria Streptococcus pneumoniae further confirms the controllable bactericide delivery mechanism. OTE-HA nanoparticles coated on a surface can also effectively inhibit the growth of bacteria, which holds a remarkable promise in biomedical applications. Therefore, this work provides a favorable strategy of on-demand and in situ drug release for sterilization and defeating antimicrobial resistance.

Synergistic non-bonding interactions based on diketopyrrolo-pyrrole for elevated photoacoustic imaging-guided photothermal therapy

Synergistic non-bonding interactions in fluorine and chalcogen-substituted diketopyrrolopyrrole nanoagents for elevated photoacoustic imaging-guided photothermal therapy.

Engineering fluorescent semiconducting polymer nanoparticles for biological applications and beyond

We summarize the recent advances in engineering approaches to obtain functionalized semiconducting polymer nanoparticles (SPNs) for biological applications. The challenges and outlook of fabricating functionalized SPNs are also provided.

Activatable Polymer Nanoenzymes for Photodynamic Immunometabolic Cancer Therapy

Tumor immunometabolism contributes substantially to tumor proliferation and immune cell activity, and thus plays a crucial role in the efficacy of cancer immunotherapy. Modulation of immunometabolism to boost cancer immunotherapy is mostly based on small-molecule inhibitors, which often encounter the issues of off-target adverse effects, drug resistance, and unsustainable response. In contrast, enzymatic therapeutics can potentially bypass these limitations but has been less exploited. Herein, an organic polymer nanoenzyme (SPNK) with near-infrared (NIR) photoactivatable immunotherapeutic effects is reported for photodynamic immunometabolic therapy. SPNK is composed of a semiconducting polymer core conjugated with kynureninase (KYNase) via PEGylated singlet oxygen (1 O2 ) cleavable linker. Upon NIR photoirradiation, SPNK generates 1 O2 not only to exert photodynamic effect to induce the immunogenic cell death of cancer, but also to unleash KYNase and trigger its activity to degrade the immunosuppressive kynurenine (Kyn). Such a combinational effect mediated by SPNK promotes the proliferation and infiltration of effector T cells, enhances systemic antitumor T cell immunity, and ultimately permits inhibition of both primary and distant tumors in living mice. Therefore, this study provides a promising photodynamic approach toward remotely controlled enzymatic immunomodulation for improved anticancer therapy.

Terselenophene Regioisomer Conjugated Polymer Materials for High-Performance Cancer Phototheranostics

Molecular isomerization is a fundamental issue in the development of functional materials, with a crucial impact on photophysical properties. However, up to now, their effect on photothermal conversion is rarely investigated. Here, two near-infrared (NIR)-absorbing regioisomer conjugated polymers integrated with cis/trans-terselenophenes are designed and synthesized as efficient photothermal agents to enhance cancer phototheranostics. It is demonstrated that enhanced quinoidal resonance of trans-terselenophenes allows the resulting trans-CP to possess more planar backbone to further increase the effective conjugation length and result in the strong absorption spectra at 808 nm. Characterization of photophysical properties has proved that the photothermal conversion efficiency of trans-CP nanoparticles is up to 61.4%, and they are 210% as strong as cis-CP nanoparticles (29.4%). Further in vitro and in vivo works demonstrate efficient photothermal therapeutic effects with the guidance of photoacoustic imaging. This work affords a new understanding of the molecular isomerization into the development of conjugated materials for high-performance cancer phototheranostics.

AIEgens for microbial detection and antimicrobial therapy

Pathogenic microbes can cause infections or diseases in hosts and they pose ongoing threats to human health. Antibiotics have been taken an active role in treating a wide variety of infections or diseases since they were first introduced in the 1940s. However, the emergence of antibiotic-resistant microbes makes these previously effective drugs invalid regrettably. So it is urgently needed to accelerate research and development for new antimicrobial systems and strategies. Recently, luminogens with aggregation-induced emission characteristics (AIEgens) have emerged as powerful fluorescent tools for microbial detection and antimicrobial therapy. In this review, we highlighted the latest advancements of AIEgen-based biofunctional materials and systems in this research field. AIE fluorescent probes have the advantages of excellent sensitivity and rapid response, which make them useful for ultrafast bacterial imaging, bacteria classification, and pathogen discrimination. Early microbial detection and identification could help us study the mechanism of antibiotic resistance more scientifically. Moreover, the AIEgens-based photosensitizers (AIE-PSs) with strong photosensitization show good performance on the efficient elimination of multidrug-resistant bacteria and intracellular bacteria. At the end of the review, a short perspective on aggregate science is concluded.

Multicomponent Polymerization toward Cationic Polymers for Efficient Gene Delivery

A new class of cationic polymers containing tertiary amine, thioether, and hydroxyl groups are prepared via a catalyst-free, multicomponent polymerization method using dithiol, formaldehyde, and di-sec-amine with a ratio of 1:2:1, to access a library of water-soluble polymers with well-defined structures and suitable molecular weights (M_w ranging from 5000 to 8000 Da) in high yields (up to 90%). Such polycations are demonstrated to be promising nonviral gene delivery vectors with high transfection efficiency (up to 3.5-fold of PEI25k) and low toxicity with multiple functionalities: 1) efficient gene condensation by tertiary amine groups; 2) reactive oxygen species scavenging by thioether groups; and 3) positive charge shielding by hydroxyl groups. Both the thioether and hydroxyl groups are contributed to reduce the cytotoxicity of the polycations by tuning the oxidative stress and preventing the undesired serum binding. The optimized polycations can achieve high transfection efficiency under the serum conditions, indicating the great potential as a nonviral gene delivery vector candidate for clinical application.

Infrared neuromodulation:a neuroengineering perspective

Infrared neuromodulation (INM) is a branch of photobiomodulation that offers direct or indirect control of cellular activity through elevation of temperature in a spatially confined region of the target tissue. Research on INM started about 15 ago and is gradually attracting the attention of the neuroscience community, as numerous experimental studies have provided firm evidence on the safe and reproducible excitation and inhibition of neuronal firing in both in vitro and in vivo conditions. However, its biophysical mechanism is not fully understood and several engineered interfaces have been created to investigate infrared stimulation in both the peripheral and central nervous system. In this review, recent applications and present knowledge on the effects of INM on cellular activity are summarized, and an overview of the technical approaches to deliver infrared light to cells and to interrogate the optically evoked response is provided. The micro- and nanoengineered interfaces used to investigate the influence of INM are described in detail.

Targeted Engineering of Medicinal Chemistry for Cancer Therapy: Recent Advances and Perspectives

Severe side effects and poor therapeutic efficacy are the main drawbacks of current anticancer drugs. These problems can be mitigated by targeting, but the targeting efficacy of current drugs is poor and urgently needs improvement. Taking this into consideration, this Review first summarizes the current targeting strategies for cancer therapy in terms of cancer tissue and organelles. Then, we analyse the systematic targeting of anticancer drugs and conclude that a typical journey for a targeted drug administered by intravenous injection is a CTIO cascade of at least four steps. Furthermore, to ensure high overall targeting efficacy, the properties of a targeting drug needed in each step are further analysed, and some guidelines for structure optimization to obtain effective targeting drugs are offered. Finally, some viewpoints highlighting the crucial problems and potential challenges of future research on targeted cancer therapy are presented. This review could actively promote the development of precision medicine against cancer.

On/off switchable epicatechin-based ultra-sensitive MRI-visible nanotheranostics - see it and treat it

Nanotechnology has a remarkable impact on the preclinical development of future medicines. However, the complicated preparation and systemic toxicity to living systems prevent them from translation to clinical applications. In the present report, we developed a polyepicatechin-based on/off switchable ultra-sensitive magnetic resonance imaging (MRI) visible theranostic nanoparticle (PEMN) for image-guided photothermal therapy (PTT) using our strategy of integrating polymerization and biomineralization into the protein template. We have exploited natural polyphenols as the near infra-red (NIR) switchable photothermal source and MnO₂ for the MRI-guided theranostics. PEMN demonstrates excellent MRI contrast ability with a longitudinal relaxivity value up to 30.01 mM^-1 s^-1. PEMN has shown great tumor inhibition on orthotopic breast tumors and the treatment could be made switchable with an on/off interchangeable mode as needed. PEMN was found to be excretable mainly through the kidneys, avoiding potential systemic toxicity. Thus, PEMN could be extremely useful for developing on-demand therapeutics via'see it and treat it' means with distinguished MRI capability and on/off switchable photothermal properties.