Phototriggered Drug Delivery Using Inorganic Nanomaterials

Bioderived Mesoporous Carbon@Tungsten Oxide Nanocomposite as a Drug Carrier Vehicle of Doxorubicin for Potent Cancer Therapy

Scientists have investigated the possibility of employing nanomaterials as drug carriers. These nanomaterials can preserve their content and transport it to the target region in the body. In this investigation, we proposed a simple method for developing distinctive, bioderived nanostructures with mesoporous carbon nanoparticles impregnated with tungsten oxide (WO3). Prior to characterizing and encapsulating WO3 with bioderived mesoporous carbon, the anticancer drug doxorubicin (DOX) was added to the nanoparticles and examined loading and release study. The approaches for both nanoparticle production and characterization are discussed in detail. Colloidal qualities of the nanomaterial can be effectively preserved while also allowing transdermal transportation of nanoparticles into the body by forming them into green, reusable, and porous nanostructures. Although the theories of nanoparticles and bioderived carbon each have been studied separately, the combination presents a new route to applications connected to nanomedicine. Furthermore, this sample was used to study exotic biomedical applications, such as antioxidant, antimicrobial, and anticancer activities. The W-3 sample had lower antioxidant activity (44.01%) than the C@W sample (56.34%), which was the most potent. A high DOX entrapment effectiveness of 97% was eventually achieved by the C@W sample, compared to a pure WO3 entrapment efficiency of 91%. It was observed that the Carbon/WO3 composite (C@W) sample showed more efficacy because the mesoporous carbon composition with WO3 increases the average surface area and surface-active locations.

Challenges and advances for glioma therapy based on inorganic nanoparticles

Glioma is one of the most serious central nervous system diseases, with high mortality and poor prognosis. Despite the continuous development of existing treatment methods, the median survival time of glioma patients is still only 15 months. The main treatment difficulties are the invasive growth of glioma and the obstruction of the blood-brain barrier (BBB) to drugs. With rapid advancements in nanotechnology, inorganic nanoparticles (INPs) have shown favourable application prospects in the diagnosis and treatment of glioma. Due to their extraordinary intrinsic features, INPs can be easily fabricated, while doping with other elements and surface modification by biological ligands can be used to enhance BBB penetration, targeted delivery and biocompatibility. Guided glioma theranostics with INPs can improve and enhance the efficacy of traditional methods such as chemotherapy, radiotherapy and gene therapy. New strategies, such as immunotherapy, photothermal and photodynamic therapy, magnetic hyperthermia therapy, and multifunctional inorganic nanoplatforms, have also been facilitated by INPs. This review emphasizes the current state of research and clinical applications of INPs, including glioma targeting and BBB penetration enhancement methods, in vivo and in vitro biocompatibility, and diagnostic and treatment strategies. As such, it provides insights for the development of novel glioma treatment strategies.

Recent Advances in Metal-Organic-Framework-Based Nanocarriers for Controllable Drug Delivery and Release

Metal-organic frameworks (MOFs) have a good designability, a well-defined pore, stimulus responsiveness, a high surface area, and a controllable morphology. Up to now, various MOFs have been widely used as nanocarriers and have attracted lots of attention in the field of drug delivery and release because of their good biocompatibility and high-drug-loading capacity. Herein, we provide a comprehensive summary of MOF-based nanocarriers for drug delivery and release over the last five years. Meanwhile, some representative examples are highlighted in detail according to four categories, including the University of Oslo MOFs, Fe-MOFs, cyclodextrin MOFs, and other MOFs. Moreover, the opportunities and challenges of MOF-based smart delivery vehicles are discussed. We hope that this review will be helpful for researchers to understand the recent developments and challenges of MOF-based drug-delivery systems.

Self-Assembled DNA-Protein Hybrid Nanospheres: Biocompatible Nano-Drug-Carriers for Targeted Cancer Therapy

We developed hybrid nanospheres comprised of two of the most important biomolecules in nature, DNA and proteins, which have excellent biocompatibility, high drug payload capacity, in vivo imaging ability, and in vitro/in vivo cancer targeting capability. The synthesis can be done in a facile one-pot assembly system that includes three steps: step-growth polymerization of two DNA oligomers, addition of streptavidin to assemble spherical hybrid nanostructures, and functionalization of hybrid nanospheres with biotinylated aptamers. To test the feasibility of cancer targeting and drug-loading capacity of the hybrid nanospheres, MUC1-specific aptamers (MA3) were conjugated to nanosphere surfaces (apt-nanospheres), and doxorubicin (Dox) was loaded into nanospheres by DNA intercalation. The successful construction of nanospheres and apt-nanospheres was confirmed by agarose gel electrophoresis and dynamic light scattering (DLS). Their uniform spherical morphology was confirmed by transmission electron microscopy (TEM). Fluorescence spectra of nanospheres demonstrated high Dox-loading capability and slow-release characteristics. In vitro MUC1-specific binding of the apt-nanospheres was confirmed by flow cytometry and confocal microscopy. Dox-loaded apt-nanospheres significantly increased cytotoxicity of the MUC1-positive cancer cells due to aptamer-mediated selective internalization, as shown via cell viability assays. Apt-nanospheres could also be imaged in vivo through the synthesis of hybrid nanospheres using fluorescent dye-conjugated DNA strands. Finally, in vivo specific targeting ability of apt-nanospheres was confirmed in a MUC1-positive 4T1 tumor-bearing mouse model, whereas apt-nanospheres did not cause any sign of systemic toxicity in normal mice. Taken together, our self-assembled DNA-streptavidin hybrid nanospheres show promise as a biocompatible cancer targeting material for contemporary nanomedical technology.

Fabrication of a magnetic nanocarrier for doxorubicin delivery based on hyperbranched polyglycerol and carboxymethyl cellulose: An investigation on the effect of borax cross-linker on pH-sensitivity

A new core-shell pH-responsive nanocarrier was prepared based on magnetic nanoparticle (MNP) core. Magnetic nanoparticles were first modified with hyperbranched polyglycerol as the first shell. Then the magnetic core was decorated with doxorubicin anticancer drug (DOX) and covered with PEGylated carboxymethylcellulose as the second shell. Borax was used to partially cross-link organic shells in order to evaluate drug loading content and pH-sensitivity. The structure of nanocarrier, organic shell loadings, magnetic responsibility, morphology, size, dispersibility, and drug loading content were investigated by IR, NMR, TG, VSM, XRD, DLS, HR-TEM and UV-Vis analyses. In vitro release investigations demonstrated that the use of borax as cross-linker between organic shells make the nanocarrier highly sensitive to pH so that more that 70% of DOX is released in acidic pH. A reverse pH-sensitivity was observed for the nanocarrier without borax cross-linker. The MTT assay determined that the nanocarrier exhibited excellent biocompatibility toward normal cells (HEK-293) and high toxicity against cancerous cells (HeLa). The nanocarrier also showed high hemocompatibility. Cellular uptake revealed high ability of nanocarrier toward HeLa cells comparable with free DOX. The results also suggested that low concentration of nanocarrier has a great potential for use as contrast agent in magnetic resonance imaging (MRI).

Near-Infrared Light-Driven Multifunctional Tubular Micromotors for Treatment of Atherosclerosis

One of the difficulties in atherosclerosis treatment is that the ablation of inflammatory macrophages, repair of vascular endothelial injury, and anti-tissue proliferation should be considered. However, there are few studies that can solve the abovementioned problems simultaneously. Herein, we present a kind of near-infrared (NIR) light-driven multifunctional mesoporous/macroporous tubular micromotor which can rapidly target the damaged blood vessels and release different drugs. Their motion effect can promote themselves to penetrate into the plaque site, and the generated heat effect caused by NIR irradiation can realize the photothermal ablation of inflammatory macrophages. Furthermore, these micromotors can rapidly release the vascular endothelial growth factor for endothelialization and slowly release paclitaxel for antiproliferation to achieve synergistic treatment of atherosclerosis. In vivo results demonstrated that the micromotors can achieve a good therapeutic effect for atherosclerosis. This kind of micro/nanomotor technology with a complex porous structure for drug loading will bring a more potential treatment platform for the disease.

Chitosan/hyaluronic acid based hollow microcapsules equipped with MXene/gold nanorods for synergistically enhanced near infrared responsive drug delivery

Ti₃C₂ MXenes, a novel two-dimensional material, have attracted lots of attention in biomedical filed for its large surface area and excellent near-infrared (NIR) responsiveness. In this paper, a pH/near-infrared (NIR) multi-responsive drug delivery platform consisted of hollow hydroxyapatite (HAP), chitosan (CS)/hyaluronic acid (HA) multilayers, gold nanorods (AuNRs) and MXene had been fabricated via a layer-by-layer (LbL) approach. Chitosan/hyaluronic acid multilayers were deposited on the surface of hollow HAP to retard the burst release of DOX in the initial delivery stage. MXenes and AuNRs equipped on the surface of hybrid matrix greatly enhanced the photothermal conversion efficiency of the microcapsules. Due to the collapse of electrostatic force among chitosan/hyaluronic acid multilayers and the dissolution of HAP under acidic condition, as well as the synergistically enhanced photothermal effect between MXene and AuNRs, HAP/CS/HA/MXene/AuNRs microcapsules exhibited outstanding pH-/NIR-responsive drug delivery properties. The present paper provides an attractive method to prepare chitosan/hyaluronic acid based pH/NIR multi-responsive hybrid microcapsules with excellent photothermal conversion efficiency and biocompatibility, which has great potential in the field of remotely controlled drug delivery.

Targeting drug delivery with light: A highly focused approach

Light is a uniquely powerful tool for controlling molecular events in biology. No other external input (e.g., heat, ultrasound, magnetic field) can be so tightly focused or so highly regulated as a clinical laser. Drug delivery vehicles that can be photonically activated have been developed across many platforms, from the simplest "caging" of therapeutics in a prodrug form, to more complex micelles and circulating liposomes that improve drug uptake and efficacy, to large-scale hydrogel platforms that can be used to protect and deliver macromolecular agents including full-length proteins. In this Review, we discuss recent innovations in photosensitive drug delivery and highlight future opportunities to engineer and exploit such light-responsive technologies in the clinical setting.

UV-trained and metal-enhanced fluorescence of biliverdin and biliverdin nanoparticles

Increasing the fluorescence quantum yield of fluorophores is of great interest for in vitro and in vivo biomedical imaging applications. At the same time, photobleaching and photodegradation resulting from continuous exposure to light are major considerations in the translation of fluorophores from research applications to industrial or healthcare applications. A number of tetrapyrrolic compounds, such as heme and its derivatives, are known to provide fluorescence contrast. In this work, we found that biliverdin (BV), a naturally-occurring tetrapyrrolic fluorophore, exhibits an increase in fluorescence quantum yield, without exhibiting photobleaching or degradation, in response to continuous ultraviolet (UV) irradiation. We attribute this increased fluorescence quantum yield to photoisomerization and conformational changes in BV in response to UV irradiation. This enhanced fluorescence can be further altered by chelating BV with metals. UV irradiation of BV led to an approximately 10-fold increase in its 365 nm fluorescence quantum yield, and the most favorable combination of UV irradiation and metal chelation led to an approximately 18.5-fold increase in its 365 nm fluorescence quantum yield. We also evaluated these stimuli-responsive behaviors in biliverdin nanoparticles (BVNPs) at the bulk-state and single-particle level. We determined that UV irradiation led to an approximately 2.4-fold increase in BVNP 365 nm quantum yield, and the combination of UV irradiation and metal chelation led to up to a 6.75-fold increase in BVNP 365 nm quantum yield. Altogether, these findings suggest that UV irradiation and metal chelation can be utilized alone or in combination to tailor the fluorescence behavior of imaging probes such as BV and BVNPs at selected wavelengths.

Recent advances in cancer photo-theranostics: the synergistic combination of transition metal complexes and gold nanostructures

In this mini review, we highlight advances in the last five years in light-activated cancer theranostics by using hybrid systems consisting of transition metal complexes (TMCs) and plasmonic gold nanostructures (AuNPs). TMCs are molecules with attractive properties and high potential in biomedical application. Due to their antiproliferative abilities, platinum-based compounds are currently first-choice drugs for the treatment of several solid tumors. Moreover, ruthenium, iridium and platinum complexes are well-known for their ability to photogenerate singlet oxygen, a highly cytotoxic reactive species with a key role in photodynamic therapy. Their potential is further extended by the unique photophysical properties, which make TMCs particularly suitable for bioimaging. Recently, gold nanoparticles (AuNPs) have been widely investigated as one of the leading nanomaterials in cancer theranostics. AuNPs—being an inert and highly biocompatible material—represent excellent drug delivery systems, overcoming most of the side effects associated with the systemic administration of anticancer drugs. Furthermore, due to the thermoplasmonic properties, AuNPs proved to be efficient nano-sources of heat for photothermal therapy application. Therefore, the hybrid combination TMC/AuNPs could represent a synergistic merger of multiple functionalities for combinatorial cancer therapy strategies. Herein, we report the most recent examples of TMC/AuNPs systems in in-vitro in-vivo cancer tharanostics application whose effects are triggered by light-exposure in the Vis–NIR region, leading to a spatial and temporal control of the TMC/AuNPs activation for light-mediated precision therapeutics.

Silver telluride nanoparticles as biocompatible and enhanced contrast agents for X-ray imaging: an in vivo breast cancer screening study

Silver sulfide nanoparticles (Ag2S NPs) have gained considerable interest in the biomedical field due to their photothermal ablation enhancement, near-infrared fluorescence properties, low toxicity levels, and multi-imaging capabilities. Silver telluride nanoparticles (Ag2Te NPs) have similar properties to Ag2S NPs, should also be stable due to an extremely low solubility product and should generate greater X-ray contrast since tellurium is significantly more attenuating than sulfur at diagnostic X-ray energies. Despite these attractive properties, Ag2Te NPs have only been studied in vivo once and at a low dose (2 mg Ag per kg). Herein, for the first time, Ag2Te NPs' properties and their application in the biomedical field were studied in vivo in the setting requiring the highest nanoparticle doses of all biomedical applications, i.e. X-ray imaging. Ag2Te NPs were shown to be stable, biocompatible (no acute toxicity observed in the cell lines studied or in vivo), and generated higher contrast, compared to controls, in the two X-ray imaging techniques studied: computed tomography (CT) and dual-energy mammography (DEM). In summary, this is the first study where Ag2Te NPs were explored in vivo at a high dose. Our findings suggest that Ag2Te NPs provide strong X-ray contrast while exhibiting excellent biocompatibility. These results highlight the potential use of Ag2Te NPs in the biomedical field and as X-ray contrast agents for breast cancer screening.

Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials

Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.

Thermochromic Hydrogel-Functionalized Textiles for Synchronous Visual Monitoring of On-Demand In Vitro Drug Release

In vitro drug release systems have recently received tremendous attention because they allow noninvasive, convenient, and prolonged administration of pharmacological agents. On-demand epidermal drug release systems can improve treatment efficiency, prevent multidrug resistance, and minimize drug toxicity to healthy cells. In addition, real-time monitoring of drug content is also essential for guiding the determination of drug dosage and replacing drug carriers in time. Therefore, it is important to integrate the above properties in one ideal epidermal patch. Herein, photonic crystals (PCs) based on Fe₃O₄@C nanoparticles were introduced into drug-loaded poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AAc)) hydrogel-functionalized textiles. Drug loading and release depended on the expansion and contraction of the hydrogels. The lower critical solution temperature (LCST) of the hydrogels was adjusted to 40 °C, which is higher than the skin temperature, by varying the content of hydrophilic comonomer acrylic acid (AAc) to store the drug at room temperature, and on-demand release was achieved by mild thermal stimulation. Moreover, the lattice spacing (d) of PCs varied with the expansion and contraction of the hydrogels, which can cause the color of P(NIPAM-AAc) hydrogel-functionalized textiles to change. These synchronous thermoresponsive chromic drug uptake and release behaviors provided an effective method for visual and real-time monitoring of drug content. Furthermore, in view of the poor mechanical properties of hydrogel wound dressings, textile matrices were composited to prevent holistic breaking during the stretching process. Biological experiments proved that the drug-loaded P(NIPAM-AAc) hydrogel-functionalized textiles had good antibacterial properties and wound-healing effects.

Core-shell nanostructures: perspectives towards drug delivery applications

Nanosystems have shown encouraging outcomes and substantial progress in the areas of drug delivery and biomedical applications. However, the controlled and targeted delivery of drugs or genes can be limited due to their physicochemical and functional properties. In this regard, core-shell type nanoparticles are promising nanocarrier systems for controlled and targeted drug delivery applications. These functional nanoparticles are emerging as a particular class of nanosystems because of their unique advantages, including high surface area, and easy surface modification and functionalization. Such unique advantages can facilitate the use of core-shell nanoparticles for the selective mingling of two or more different functional properties in a single nanosystem to achieve the desired physicochemical properties that are essential for effective targeted drug delivery. Several types of core-shell nanoparticles, such as metallic, magnetic, silica-based, upconversion, and carbon-based core-shell nanoparticles, have been designed and developed for drug delivery applications. Keeping the scope, demand, and challenges in view, the present review explores state-of-the-art developments and advances in core-shell nanoparticle systems, the desired structure-property relationships, newly generated properties, the effects of parameter control, surface modification, and functionalization, and, last but not least, their promising applications in the fields of drug delivery, biomedical applications, and tissue engineering. This review also supports significant future research for developing multi-core and shell-based functional nanosystems to investigate nano-therapies that are needed for advanced, precise, and personalized healthcare systems.

Delivery of drugs, proteins, and nucleic acids using inorganic nanoparticles

Inorganic nanoparticles provide multipurpose platforms for a broad range of delivery applications. Intrinsic nanoscopic properties provide access to unique magnetic and optical properties. Equally importantly, the structural and functional diversity of gold, silica, iron oxide, and lanthanide-based nanocarriers provide unrivalled control of nanostructural properties for effective transport of therapeutic cargos, overcoming biobarriers on the cellular and organismal level. Taken together, inorganic nanoparticles provide a key addition to the arsenal of delivery vectors for fighting disease and improving human health.

Photosensitive nanocarriers for specific delivery of cargo into cells

Nanoencapsulation is a rapidly expanding technology to enclose cargo into inert material at the nanoscale size, which protects cargo from degradation, improves bioavailability and allows for controlled release. Encapsulation of drugs into functional nanocarriers enhances their specificity, targeting ability, efficiency, and effectiveness. Functionality may come from cell targeting biomolecules that direct nanocarriers to a specific cell or tissue. Delivery is usually mediated by diffusion and erosion mechanisms, but in some cases, this is not sufficient to reach the expected therapeutic effects. This work reports on the development of a new photoresponsive polymeric nanocarrier (PNc)-based nanobioconjugate (NBc) for specific photo-delivery of cargo into target cells. We readily synthesized the PNcs by modification of chitosan with ultraviolet (UV)-photosensitive azobenzene molecules, with Nile red and dofetilide as cargo models to prove the encapsulation/release concept. The PNcs were further functionalized with the cardiac targeting transmembrane peptide and efficiently internalized into cardiomyocytes, as a cell line model. Intracellular cargo-release was dramatically accelerated upon a very short UV-light irradiation time. Delivering cargo in a time-space controlled fashion by means of NBcs is a promising strategy to increase the intracellular cargo concentration, to decrease dose and cargo side effects, thereby improving the effectiveness of a therapeutic regime.

Metal-Organic Frameworks as a Theranostic Nanoplatform for Combinatorial Chemophotothermal Therapy Adapted to Different Administration

With the rapid development of nanotechnology, nanomaterial drug delivery systems have provided an alternative for designing controllable drug delivery systems due to their spatiotemporally controllable properties. As a new type of porous material, metal-organic frameworks (MOFs) have been widely used in biomedical applications, especially drug delivery systems, owing to their tunable pore size, high surface area and pore volume, and easy surface modification. Here, we demonstrate an MOF as a theranostic nanoplatform to combine drug therapy and phototherapy after labeling targeting peptide iRGD. The micropore Fe-MOF was used as MRI agents for locating tumors and as nanocarriers to upload chemotherapeutic drugs. Moreover, MOF showed excellent targeting performance under different administration including intravenous injection for breast cancer and local instillation for bladder cancer. Notably, when irradiated with an 808 nm laser, the agent demonstrates the high efficacy of photothermal therapy and heat release efficiency of the drug around the tumor site. This combination therapy provides an alternative drug administration method and can be adapted to a series of cancer cell types and molecular targets associated with disease progression.

Multicomponent Plasmonic Nanoparticles: From Heterostructured Nanoparticles to Colloidal Composite Nanostructures

Plasmonic nanostructures possessing unique and versatile optoelectronic properties have been vastly investigated over the past decade. However, the full potential of plasmonic nanostructure has not yet been fully exploited, particularly with single-component homogeneous structures with monotonic properties, and the addition of new components for making multicomponent nanoparticles may lead to new-yet-unexpected or improved properties. Here we define the term "multi-component nanoparticles" as hybrid structures composed of two or more condensed nanoscale domains with distinctive material compositions, shapes, or sizes. We reviewed and discussed the designing principles and synthetic strategies to efficiently combine multiple components to form hybrid nanoparticles with a new or improved plasmonic functionality. In particular, it has been quite challenging to precisely synthesize widely diverse multicomponent plasmonic structures, limiting realization of the full potential of plasmonic heterostructures. To address this challenge, several synthetic approaches have been reported to form a variety of different multicomponent plasmonic nanoparticles, mainly based on heterogeneous nucleation, atomic replacements, adsorption on supports, and biomolecule-mediated assemblies. In addition, the unique and synergistic features of multicomponent plasmonic nanoparticles, such as combination of pristine material properties, finely tuned plasmon resonance and coupling, enhanced light-matter interactions, geometry-induced polarization, and plasmon-induced energy and charge transfer across the heterointerface, were reported. In this review, we comprehensively summarize the latest advances on state-of-art synthetic strategies, unique properties, and promising applications of multicomponent plasmonic nanoparticles. These plasmonic nanoparticles including heterostructured nanoparticles and composite nanostructures are prepared by direct synthesis and physical force- or biomolecule-mediated assembly, which hold tremendous potential for plasmon-mediated energy transfer, magnetic plasmonics, metamolecules, and nanobiotechnology.

Method for the Instant In-Flight Manufacture of Black Phosphorus to Assemble Core@Shell Nanocomposites for Targeted Photoimmunotherapy

Inorganic nanomaterial (INM)-based combination cancer therapies have been extensively employed over the past two decades because of their benefits over traditional chemo- and radiotherapies. However, issues regarding the toxicity and accumulation of INMs in the body have arisen. This problem may be improved through the use of biodegradable or disintegrable nanosystems such as black phosphorus (BP). Challenges to the manufacture of fully nanodimensional BP remain. In addition, improvements in recently developed cancer immunotherapies require their incorporation with drugs, targeting agents, and delivery vehicles. With these needs in mind, this study develops a method for instant in-flight manufacture of nanodimensional BP using plug-and-play devices for subsequent assembly of photoimmunotherapeutic core@shell composites containing mutated B-raf inhibitors (dabrafenib), immune checkpoint inhibitors (PD-L1), and cancer-targeting antibodies (CXCR4). The resulting nanocomposites exhibited cancer targetability and regulatability of PD-L1 expression both in vitro and in vivo. These activities were further increased upon near-infrared irradiation due to the incorporation of a phototherapeutic component. These results suggest that these nanocomposites are promising as a new class of advanced cancer therapeutic agents.

Light-triggered release of photocaged therapeutics - Where are we now?

The current available therapeutics face several challenges such as the development of ideal drug delivery systems towards the goal of personalized treatments for patients benefit. The application of light as an exogenous activation mechanism has shown promising outcomes, owning to the spatiotemporal confinement of the treatment in the vicinity of the diseased tissue, which offers many intriguing possibilities. Engineering therapeutics with light responsive moieties have been explored to enhance the bioavailability, and drug efficacy either in vitro or in vivo. The tailor-made character turns the so-called photocaged compounds highly desirable to reduce the side effects of drugs and, therefore, have received wide research attention. Herein, we seek to highlight the potential of photocaged compounds to obtain a clear understanding of the mechanisms behind its use in therapeutic delivery. A deep overview on the progress achieved in the design, fabrication as well as current and possible future applications in therapeutics of photocaged compounds is provided, so that novel formulations for biomedical field can be designed.

SS, Paggi M, Bordas SP. Advances in Carbon Based Nanomaterials for Bio-Medical Applications

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The unique mechanical, electrical, thermal, chemical and optical properties of carbon based nanomaterials (CBNs) like: Fullerenes, Graphene, Carbon nanotubes, and their derivatives made them widely used materials for various applications including biomedicine. Few recent applications of the CBNs in biomedicine include: cancer therapy, targeted drug delivery, bio-sensing, cell and tissue imaging and regenerative medicine. However, functionalization renders the toxicity of CBNs and makes them soluble in several solvents including water, which is required for biomedical applications. Hence, this review represents the complete study of development in nanomaterials of carbon for biomedical uses. Especially, CBNs as the vehicles for delivering the drug in carbon nanomaterials is described in particular. The computational modeling approaches of various CBNs are also addressed. Furthermore, prospectus, issues and possible challenges of this rapidly developing field are highlighted.

Methotrexate-based amphiphilic prodrug nanoaggregates for co-administration of multiple therapeutics and synergistic cancer therapy

The goal of nanomedicine is to seek strategies that are more efficient to address various limitations and challenges faced by conventional medicines, including lack of target specificity, poor bioavailability, premature degradability, and undesired side effects. Self-assembling drug amphiphiles represent a prospective nanomedicine for cancer therapy owing to their favorable route of administration and therapeutic efficiency compared with pristine drug counterparts. In this work, we report a class of self-deliverable prodrug amphiphiles consisting of the hydrophilic drug methotrexate (MTX) and the hydrophobic anticancer drugs camptothecin (CPT) and doxorubicin (DOX) for targeted and combinational chemotherapy. The disulfide bond and hydrazone bond, which are subject to stimuli-triggered bond cleavage, were introduced to link these therapeutic agents and form two prodrug amphiphiles, named as MTX-CPT and MTX-DOX, respectively, which could self-assemble into stable prodrug nanoaggregates (NAs) in aqueous media. MTX molecules in the prodrug NAs facilitated NA uptake into tumor cells with high expression of folic acid receptors (FRs). This systemic study provided clear evidence of the synergistic therapeutic effect by co-administrating dual prodrug NAs on various tumor cells in vitro and a xenograft tumor model in vivo. The obtained prodrug amphiphiles provide an efficient strategy for the design of multifunctional drug delivery systems and elaborate therapeutic nanoplatforms for cancer chemotherapy.

STATEMENT OF SIGNIFICANCE

This work presents two kinds of prodrug amphiphiles that are carrier free and integrate targeted drug delivery, stimuli-triggered drug release, synergistic therapy, and theranostic function into a single system. Reduction/acid active prodrug amphiphiles can self-assemble into micellar nanoaggregates (NAs) at a very low critical aggregation concentration. These NAs exhibit superior stability in physiological environment and disassemble in the presence of tumor cells expressing folic acid receptors or the high glutathione or in low pH tumoral endosomal environment. The induced disassembly of prodrug NAs can "switch on" the inherent fluorescence of the internalized camptothecin or doxorubicin for the detection of tumor cells. Compared to a single type of prodrug NA, co-administration of dual prodrug combination can produce an evident synergistic therapeutic effect against various tumor cells in vitro and inhibit xenograft tumor growth in vivo. The methotrexate-based prodrug amphiphiles may provide a potential strategy for developing multifunctional nanoplatforms and delivery of multiple therapeutics in chemotherapy.

Seeing, Targeting and Delivering with Upconverting Nanoparticles

Efficient control over drug release is critical to increasing drug efficacy and avoiding side effects. An ideal drug delivery system would deliver drugs in the right amount, at the right location and at the right time noninvasively. This can be achieved using light-triggered delivery: light is noninvasive, spatially precise and safe if appropriate wavelengths are chosen. However, the use of light-controlled delivery systems has been limited to areas that are not too deep inside the body because ultraviolet (UV) or visible (Vis) light, the typical wavelengths used for photoreactions, have limited penetration and are toxic to biological tissues. The advent of upconverting nanoparticles (UCNPs) has made it possible to overcome this crucial challenge. UCNPs can convert near-infrared (NIR) radiation, which can penetrate deeper inside the body, to shorter wavelength NIR, Vis and UV radiation. UCNPs have been used as bright, in situ sources of light for on-demand drug release and bioimaging applications. These remote-controlled, NIR-triggered drug delivery systems are especially attractive in applications where a drug is required at a specific location and time such as in anesthetics, postwound healing, cardiothoracic surgery and cancer treatment. In this Perspective, we discuss recent progress and challenges as well as propose potential solutions and future directions, especially with regard to their translation to the clinic.

Multifunctional Yolk-Shell Mesoporous Silica Obtained via Selectively Etching the Shell: A Therapeutic Nanoplatform for Cancer Therapy

Herein, we fabricated a new yolk-shell-structured mesoporous silica nanoparticle (YMSN) with multifunctionalities of fluorescence imaging, photothermal therapy (PTT), and drug delivery by using a fluorescein isothiocyanate-doped silica nanoparticle partially covered by patchy gold as the core. Different from the conventional selective etching procedure, the multifunctional silica core is left intact, and the alkali etching mainly occurs in a hexadecyl trimethyl ammonium bromide/silica hybrid layer, which leads to the formation of the void space in YMSNs. In addition, the utilization of patchy gold as the PTT agent can avoid the shield against the outer irradiation on the core. Results show that the as-prepared YMSNs have a good biocompatibility in the concentration of 0-1000 μg·mL^-1 and a high doxorubicin-loading capability (8.04 wt %). In vitro and in vivo antitumor experiments reveal that the resulting YMSNs can be utilized for chemo- and photothermic combination therapy as well as optical imaging.

In vitro and In vivo Studies on a Novel Bioadhesive Colloidal System: Cationic Liposomes of Ibuprofen

The objective of this study was to develop an ocular drug delivery system built on the cationic liposomes, a novel bioadhesive colloidal system, which could enhance the precorneal residence time, ocular permeation, and bioavailability of ibuprofen. The optimal formulation of cationic liposomes prepared by ethanol injection method was ultimately confirmed by an orthogonal L₉ (3³) test design. In addition, γ-scintigraphic technology and the microdialysis technique were utilized in the assessment of in vivo precorneal retention capability and ocular bioavailability individually. In the end, we acquired the optimal formulation of ibuprofen cationic liposomes (Ibu-CL) by orthogonal test design, and the particle size and entrapment efficiency (EE%) were 121.0 ± 3.5 nm and 72.9 ± 3.4%, respectively. In comparison to ibuprofen eye drops (Ibu-ED), Ibu-CL could significantly prolong the T _max to 100 min and the AUC to 1.53-folds, which indicated that the Ibu-CL could improve the precorneal retention time and bioavailability of ibuprofen. Consequently, these outcomes designated that the ibuprofen cationic liposomes we researched probably are a promising application in ocular drug delivery system.

Silver Nanoparticles Covered with pH-Sensitive Camptothecin-Loaded Polymer Prodrugs: Switchable Fluorescence "Off" or "On" and Drug Delivery Dynamics in Living Cells

A unique drug delivery system, in which silver nanoparticles (AgNPs) are covered with camptothecin (CPT)-based polymer prodrug, has been developed, and the polymer prodrug, in which the CPT is linked to the polymer side chains via an acid-labile β-thiopropionate bond, is prepared by RAFT polymerization. For poly(2-(2-hydroxyethoxy)ethyl methacrylate-co-methacryloyloxy-3-thiahexanoyl-camptothecin)@AgNPs [P(HEO₂MA-co-MACPT)@AgNPs], the polymer thickness on the AgNP surface is around 5.9 nm (TGA method). In vitro tests in buffer solutions at pH = 7.4 reveal that fluorescence of the CPT in the hybrid nanoparticles is quenched due to the nanoparticle surface energy transfer (NSET) effect, but under acidic conditions, the CPT fluorescence is gradually recovered with gradual release of the CPT molecules from the hybrid nanoparticles through cleavage of the acid-labile bond. The NSET "on" and "off" is induced by the CPT-AgNP distance change. This unique property makes it possible to track the CPT delivery and release process from the hybrid nanoparticles in the living cells in a real-time manner. The internalization and intracellular releasing tests of the hybrid nanoparticles in the HeLa cells demonstrate that the lysosome containing the hybrid nanoparticles displays CPT blue fluorescence due to release of the CPT under acidic conditions, and the drug-releasing kinetics shows fluorescence increase of the released CPT with incubation time. The cytotoxicity of hybrid nanoparticles is dependent on activity of the acid-labile bond. Therefore, this is a potential efficient drug delivery system in cancer therapy and a useful approach to study the mechanism of release process in the cells.

Therapeutic targeting in nanomedicine: the future lies in recombinant antibodies

The unique chemical and functional properties of nanoparticles can be harnessed for the delivery of large quantities of various therapeutic biomolecules. Active targeting of nanoparticles by conjugating ligands that bind to target cells strongly facilitates accumulation, internalization into target cells and longer retention at the target site, with consequent enhanced therapeutic effects. Recombinant antibodies with high selectivity and availability for a vast range of targets will dominate the future. In this review, we systematically outline the tremendous progress in the conjugation of antibodies to nanoparticles and the clear advantages that recombinant antibodies offer in the therapeutic targeting of nanoparticles. The demonstrated flexibility of recombinant antibody coupling to nanoparticles highlights the bright future of this technology for modern therapeutic nanomedicine.

Emerging strategies in near-infrared light triggered drug delivery using organic nanomaterials

Near-infrared light has significant advantages for light-triggered drug delivery systems within deep tissues.