Release of anti-inflammatory peptides from thermosensitive nanoparticles with degradable cross-links suppresses pro-inflammatory cytokine production

Thermosensitive Polymeric Nanoparticles for Drug Co-Encapsulation and Breast Cancer Treatment

Despite advances in breast cancer treatment, there remains a need for local management of noninvasive, low-grade ductal carcinoma in situ (DCIS). These focal lesions are well suited for local intraductal treatment. Intraductal administration supported target site drug retention, improved efficacy, and reduced systemic exposure. Here, we used a poly(N-isopropyl acrylamide, pNIPAM) nanoparticle delivery system loaded with cytotoxic piplartine and an MAPKAP Kinase 2 inhibitor (YARA) for this purpose. For tumor environment targeting, a collagen-binding peptide SILY (RRANAALKAGELYKSILYGSG-hydrazide) was attached to pNIPAM nanoparticles, and the nanoparticle diameter, zeta potential, drug loading, and release were assessed. The system was evaluated for cytotoxicity in a 2D cell culture and 3D spheroids. In vivo efficacy was evaluated using a chemical carcinogenesis model in female Sprague-Dawley rats. Nanoparticle delivery significantly reduced the IC50 of piplartine (4.9 times) compared to the drug in solution. The combination of piplartine and YARA in nanoparticles further reduced the piplartine IC50 (~15 times). Treatment with these nanoparticles decreased the in vivo tumor incidence (5.2 times). Notably, the concentration of piplartine in mammary glands treated with nanoparticles (35.3 ± 22.4 μg/mL) was substantially higher than in plasma (0.7 ± 0.05 μg/mL), demonstrating targeted drug retention. These results indicate that our nanocarrier system effectively reduced tumor development with low systemic exposure.

Collagen-Binding Nanoparticles for Paclitaxel Encapsulation and Breast Cancer Treatment

In this study, we developed a novel hybrid collagen-binding nanocarrier for potential intraductal administration and local breast cancer treatment. The particles were formed by the encapsulation of nanostructured lipid carriers (NLCs) containing the cytotoxic drug paclitaxel within a shell of poly(N-isopropylacrylamide) (pNIPAM), and were functionalized with SILY, a peptide that binds to collagen type I (which is overexpressed in the mammary tumor microenvironment) to improve local retention and selectivity. The encapsulation of the NLCs in the pNIPAM shell increased nanoparticle size by approximately 140 nm, and after purification, a homogeneous system of hybrid nanoparticles (∼96%) was obtained. The nanoparticles exhibited high loading efficiency (<76%) and were capable of prolonging paclitaxel release for up to 120 h. SILY-modified nanoparticles showed the ability to bind to collagen-coated surfaces and naturally elaborated collagen. Hybrid nanoparticles presented cytotoxicity up to 3.7-fold higher than pNIPAM-only nanoparticles on mammary tumor cells cultured in monolayers. In spheroids, the increase in cytotoxicity was up to 1.8-fold. Compared to lipid nanoparticles, the hybrid nanoparticle modified with SILY increased the viability of nontumor breast cells by up to 1.59-fold in a coculture model, suggesting the effectiveness and safety of the system.

Chitosan hydrogels with MK2 inhibitor peptide-loaded nanoparticles to treat atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that lacks ideal long-term treatment options due to a series of side effects, such as skin atrophy, related to the most common treatment prescribed to manage moderate-to-severe AD. In this study, a cell-penetrating MK2 inhibitor peptide YARA (YARAAARQARAKALNRQGLVAA) was loaded into hollow thermo-responsive pNIPAM nanoparticles (NP), which were further incorporated into chitosan hydrogels (H-NP-YARA) to promote local drug delivery, improve moisture and the anti-inflammatory activity. The NPs exhibited high loading efficiency (>50%) and the hydrogel remained porous following NP incorporation as observed by scanning electron microscopy (SEM). Both nanoparticles and hydrogels were able to improve the release of YARA and sustained release to up to 120 h. The hydrogels and NPs delivered 2 and 4-fold more YARA into viable skin layers of porcine skin in vitro at 12 h post-application than the non-encapsulated compound in intact and impaired barrier conditions. Furthermore, the YARA-loaded NPs (NP-YARA) and H-NP-YARA treatment decreased the levels of inflammatory cytokines up to 20 time-fold compared with the non-treated group of human keratinocytes under inflammatory conditions. Consistent with the results in cell culture, the loading of YARA in NP reduced the levels of IL-1β, IL-6, and TNF-α up to 3.3 times in an ex vivo skin culture model after induction of inflammation. A further decrease of up to 17 times-fold was observed with H-NP-YARA treatment compared to the drug in solution. Our data collectively suggest that chitosan hydrogel containing YARA-loaded nanoparticles is a promising new formulation for the topical treatment of AD.

Particle carriers for controlled release of peptides

There has been growing discovery and use of therapeutic peptides in drug delivery and tissue engineering. Peptides are smaller than proteins and can be formulated into drug delivery systems without significant loss of their bioactivity, which remains a concern with proteins. However, the smaller size of peptides has made the controlled release of these bioactive molecules from carriers challenging. Thus, there has been increasing development of carriers to improve the controlled release of peptides by leveraging hydrophobic and electrostatic interactions between the peptide and the carrier. The focus of this review paper is to critically discuss synthetic and natural nanoparticles and microparticles that have been investigated for the controlled delivery of peptides with emphasis on the underlying interactions.

Temperature-responsive and biocompatible nanocarriers based on clay nanotubes for controlled anti-cancer drug release

Administration of temperature-responsive drug carriers that release anticancer drugs at high temperatures can benefit hyperthermia therapies because of the synergistic effect of anticancer drug molecules and high temperature on killing the cancer cells. In this study, we design and characterize a new temperature-responsive nanocarrier based on a naturally occurring and biocompatible clay mineral, halloysite nanotubes. Poly(N-isopropylacrylamide) brushes were grown on the surface of halloysite nanotubes using a combination of mussel-inspired dopamine polymerization and surface-initiated atom transfer radical polymerization. The chemical structure of the hybrid materials was investigated using X-ray photoelectron spectroscopy, thermogravimetric analysis and energy-dispersive X-ray spectroscopy. The hybrid material was shown to have a phase transition temperature of about 32 °C, corresponding to a 40 nm thick polymer layer surrounding the nanotubes. Cell studies suggested that grafting of poly(N-isopropylacrylamide) brushes on the polydopamine-modified halloysite nanotubes suppresses the cytotoxicity caused by the polydopamine interlayer and drug release studies on nanotubes loaded with doxorubicin showed that thanks to the poly(N-isopropylacrylamide) brushes a temperature-dependent drug release is observed. Finally, a fluorescent dye molecule was covalently attached to the polymer-grafted nanotubes and stimulated emission depletion nanoscopy was used to confirm the internalization of the nanotubes in HeLa cells.

Bioresponsive Immunotherapeutic Materials

The human immune system is an interaction network of biological processes, and its dysfunction is closely associated with a wide array of diseases, such as cancer, infectious diseases, tissue damage, and autoimmune diseases. Manipulation of the immune response network in a desired and controlled fashion has been regarded as a promising strategy for maximizing immunotherapeutic efficacy and minimizing side effects. Integration of "smart" bioresponsive materials with immunoactive agents including small molecules, biomacromolecules, and cells can achieve on-demand release of agents at targeted sites to reduce overdose-related toxicity and alleviate off-target effects. This review highlights the design principles of bioresponsive immunotherapeutic materials and discusses the critical roles of controlled release of immunoactive agents from bioresponsive materials in recruiting, housing, and manipulating immune cells for evoking desired immune responses. Challenges and future directions from the perspective of clinical translation are also discussed.

Recent Advances in the Biomedical Applications of Functionalized Nanogels

Nanomaterials have been extensively used in several applications in the past few decades related to biomedicine and healthcare. Among them, nanogels (NGs) have emerged as an important nanoplatform with the properties of both hydrogels and nanoparticles for the controlled/sustained delivery of chemo drugs, nucleic acids, or other bioactive molecules for therapeutic or diagnostic purposes. In the recent past, significant research efforts have been invested in synthesizing NGs through various synthetic methodologies such as free radical polymerization, reversible addition-fragmentation chain-transfer method (RAFT) and atom transfer radical polymerization (ATRP), as well as emulsion techniques. With further polymeric functionalizations using activated esters, thiol-ene/yne processes, imines/oximes formation, cycloadditions, nucleophilic addition reactions of isocyanates, ring-opening, and multicomponent reactions were used to obtain functionalized NGs for targeted delivery of drug and other compounds. NGs are particularly intriguing for use in the areas of diagnosis, analytics, and biomedicine due to their nanodimensionality, material characteristics, physiological stability, tunable multi-functionality, and biocompatibility. Numerous NGs with a wide range of functionalities and various external/internal stimuli-responsive modalities have been possible with novel synthetic reliable methodologies. Such continuous development of innovative, intelligent materials with novel characteristics is crucial for nanomedicine for next-generation biomedical applications. This paper reviews the synthesis and various functionalization strategies of NGs with a focus on the recent advances in different biomedical applications of these surface modified/functionalized single-/dual-/multi-responsive NGs, with various active targeting moieties, in the fields of cancer theranostics, immunotherapy, antimicrobial/antiviral, antigen presentation for the vaccine, sensing, wound healing, thrombolysis, tissue engineering, and regenerative medicine.

Hyaluronic Acid-Conjugated PLGA Nanoparticles Alleviate Ulcerative Colitis via CD44-Mediated Dual Targeting to Inflamed Colitis Tissue and Macrophages

Although various local anti-inflammatory therapies for ulcerative colitis have been developed, rapid drug elimination from inflamed colitis tissue and off-target side effects reduce their therapeutic efficacy. In this study, we synthesized curcumin (Cur)-loaded hyaluronic acid (HA)-conjugated nanoparticles (Cur-HA-PLGA-NPs) that target inflamed colitis tissue via HA-CD44 interaction with resident colonic epithelial cells and subsequently target activated macrophages for ulcerative colitis therapy. The synthesized spherical Cur-HA-PLGA-NPs showed physicochemical properties similar to those of non-HA-conjugated Cur-PLGA-NPs. HA-PLGA-NPs exhibited selective accumulation in inflamed colitis tissue with minimal accumulation in healthy colon tissue. HA functionalization enhanced targeted drug delivery to intestinal macrophages, significantly increasing HA-PLGA-NP cellular uptake. Importantly, the rectal administration of Cur-HA-PLGA-NPs exhibited better therapeutic efficacy than Cur-PLGA-NPs in animal studies. Histological examination revealed that Cur-HA-PLGA-NPs reduced inflammation with less inflammatory cell infiltration and accelerated recovery with re-epithelialization signs. Our results suggest that Cur-HA-PLGA-NPs are a promising delivery platform for treating ulcerative colitis.

Hyaluronic Acid-Binding, Anionic, Nanoparticles Inhibit ECM Degradation and Restore Compressive Stiffness in Aggrecan-Depleted Articular Cartilage Explants

Joint trauma results in the production of inflammatory cytokines that stimulate the secretion of catabolic enzymes, which degrade articular cartilage. Molecular fragments of the degraded articular cartilage further stimulate inflammatory cytokine production, with this process eventually resulting in post-traumatic osteoarthritis (PTOA). The loss of matrix component aggrecan occurs early in the progression of PTOA and results in the loss of compressive stiffness in articular cartilage. Aggrecan is highly sulfated, associates with hyaluronic acid (HA), and supports the compressive stiffness in cartilage. Presented here, we conjugated the HA-binding peptide GAHWQFNALTVRGSG (GAH) to anionic nanoparticles (hNPs). Nanoparticles conjugated with roughly 19 GAH peptides, termed 19 GAH-hNP, bound to HA in solution and increased the dynamic viscosity by 94.1% compared to an HA solution treated with unconjugated hNPs. Moreover, treating aggrecan-depleted (AD) cartilage explants with 0.10 mg of 19 GAH-hNP restored the cartilage compressive stiffness to healthy levels six days after a single nanoparticle treatment. Treatment of AD cartilage with 0.10 mg of 19 GAH-hNP inhibited the degradation of articular cartilage. Treated AD cartilage had 409% more collagen type II and 598% more GAG content than untreated-AD explants. The 19 GAH-hNP therapeutic slowed ECM degradation in AD cartilage explants, restored the compressive stiffness of damaged cartilage, and showed promise as a localized treatment for PTOA.

Inflammation-responsive delivery systems for the treatment of chronic inflammatory diseases

Inflammation is the biological response of immune system to protect living organisms from injurious factors. However, excessive and uncontrolled inflammation is implicated in a variety of devastating chronic diseases including atherosclerosis, inflammatory bowel disease (IBD), and rheumatoid arthritis (RA). Improved understanding of inflammatory response has unveiled a rich assortment of anti-inflammatory therapeutics for the treatment and management of relevant chronic diseases. Notwithstanding these successes, clinical outcomes are variable among patients and serious adverse effects are often observed. Moreover, there exist some limitations for clinical anti-inflammatory therapeutics such as aqueous insolubility, low bioavailability, off-target effects, and poor accessibility to subcellular compartments. To address these challenges, the rational design of inflammation-specific drug delivery systems (DDSs) holds significant promise. Moreover, as compared to normal tissues, inflamed tissue-associated pathological milieu (e.g., oxidative stress, acidic pH, and overexpressed enzymes) provides vital biochemical stimuli for triggered delivery of anti-inflammatory agents in a spatiotemporally controlled manner. In this review, we summarize recent advances in the development of anti-inflammatory DDSs with built-in pathological inflammation-specific responsiveness for the treatment of chronic inflammatory diseases.

Polymer particles for the intra-articular delivery of drugs to treat osteoarthritis

Osteoarthritis (OA) is a leading cause of chronic disability. It is a progressive disease, involving pathological changes to the entire joint, resulting in joint pain, stiffness, swelling, and loss of mobility. There is currently no disease-modifying pharmaceutical treatment for OA, and the treatments that do exist suffer from significant side effects. An increasing understanding of the molecular pathways involved in OA is leading to many potential drug targets. However, both current and new therapies can benefit from a targeted approach that delivers drugs selectively to joints at therapeutic concentrations, while limiting systemic exposure to the drugs. Delivery systems including hydrogels, liposomes, and various types of particles have been explored for intra-articular drug delivery. This review will describe progress over the past several years in the development of polymer-based particles for OA treatment, as well as their in vitro, in vivo, and clinical evaluation. Systems based on biopolymers such as polysaccharides and polypeptides, as well as synthetic polyesters, poly(ester amide)s, thermoresponsive polymers, poly(vinyl alcohol), amphiphilic polymers, and dendrimers will be described. We will discuss the role of particle size, biodegradability, and mechanical properties in the behavior of the particles in the joint, and the challenges to be addressed in future research.

Intra-articular injection of anti-inflammatory peptide-loaded glycol chitosan/fucoidan nanogels to inhibit inflammation and attenuate osteoarthritis progression

Glycol chitosan/fucoidan nanogels loaded with anti-inflammatory peptide KAFAK (GC/Fu@KAFAK NGs) were fabricated based on the electrostatic interaction and genipin cross-linking methods. The prepared NGs had an average size of 286.3 ± 5.0 nm and positive surface charge of 14.0 ± 0.2 mV. The anti-inflammatory and chondro-protective effects of GC/Fu@KAFAK NGs were evaluated on interlecukin-1β (IL-1β)-stimulated rat chondrocytes. We found that GC/Fu@KAFAK NGs not only inhibited the expression of inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), but also enhanced the expression of chondrogenic markers type II collagen, aggrecan, and Sox9. More importantly, in rat osteoarthritis (OA) model, the intra-articular (IA) injection of GC/Fu@KAFAK NGs reduced glycosaminoglycan loss and diminished inflammatory cytokine release. In addition, GC/Fu@KAFAK NGs showed good biocompatibility both in vitro and in vivo. In conclusion, IA inject-able GC/Fu@KAFAK NGs might have great potential in OA treatment.

Advanced nanomedicines for the treatment of inflammatory diseases

Inflammation, a common feature of many diseases, is an essential immune response that enables survival and maintains tissue homeostasis. However, in some conditions, the inflammatory process becomes detrimental, contributing to the pathogenesis of a disease. Targeting inflammation by using nanomedicines (i.e. nanoparticles loaded with a therapeutic active principle), either through the recognition of molecules overexpressed onto the surface of activated macrophages or endothelial cells, or through enhanced vasculature permeability, or even through biomimicry, offers a promising solution for the treatment of inflammatory diseases. After providing a brief insight on the pathophysiology of inflammation and current therapeutic strategies, the review will discuss, at a pre-clinical stage, the main innovative nanomedicine approaches that have been proposed in the past five years for the resolution of inflammatory disorders, finally focusing on those currently in clinical trials.

Thermoresponsive, hollow, degradable core-shell nanoparticles for intra-articular delivery of anti-inflammatory peptide

Inflammation following joint trauma contributes to cartilage degradation and progression of post traumatic osteoarthritis (PTOA). Therefore, drug delivery vehicles that deliver effective anti-inflammatory treatments have the potential to prevent PTOA. We have developed solid and hollow, thermoresponsive nanoparticles for the controlled release of our anti-inflammatory MK2-inhibiting (MK2i) peptide for intra-articular injection to halt inflammation that contributes to the advancement of PTOA. This system exploits the thermosensitive characteristic of N-isopropyl acrylamide (NIPAm) to transition phases when passing through its lower critical solution temperature (LCST). The nanoparticles (NPs) swell below the LCST and constrict above it. Non-crosslinked poly(NIPAm) (pNIPAm), held above its LCST, formed hydrophobic cores around which shells composed of NIPAm, degradable crosslinker N, N'-bis (acryloyl) cystamine (BAC), sulfated 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and acrylic acid (AAc) were polymerized. Removal of the non-crosslinked pNIPAm cores via diffusion produced thermosensitive, degradable nanoparticles with low density, or hollow, cores. The data presented here revealed low-density, termed hollow, nanoparticles (hNPs) load and release significantly more MK2i than solid nanoparticles (sNPs). Furthermore, drug loading below the LCST of NIPAm results in roughly 2.5 times more therapeutic encapsulation compared to loading particles in their constricted state. Hollow nanoparticles increase drug loading compared to solid nanoparticles, are taken up into chondrocytes within 24 h, cleared from the cells within 6 days, significantly decrease the secretion of the proinflammatory cytokine IL-6, and, via intra-articular injection, are successfully delivered into the joint space of rats. The peptide loaded nanoparticles provide a reproducible platform for intra-articular delivery of therapeutics.

Biomaterial-engineered intra-articular drug delivery systems for osteoarthritis therapy

Osteoarthritis (OA) is a progressive and degenerative disease, which is no longer confined to the elderly. So far, current treatments are limited to symptom relief, and no valid OA disease-modifying drugs are available. Additionally, OA relative joint is challenging for drug delivery, since the drugs experience rapid clearance in joint, showing a poor bioavailability. Existing therapeutic drugs, like non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, are not conducive for long-term use due to adverse effects. Though supplementations, including chondroitin sulfate and glucosamine, have shown beneficial effects on joint tissues in OA, their therapeutic use is still debatable. New emerging agents, like Kartogenin (KGN) and Interleukin-1 receptor antagonist (IL-1 ra), without a proper formulation, still will not work. Therefore, it is urgent to establish a suitable and efficient drug delivery system for OA therapy. In this review, we pay attention to various types of drug delivery systems and potential therapeutic drugs that may escalate OA treatments.

Natural and synthetic polymer-based smart biomaterials for management of ulcerative colitis: a review of recent developments and future prospects

Ulcerative colitis (UC) is an inflammatory disease of the colon that severely affects the quality of life of patients and usually responds well to anti-inflammatory agents for symptomatic relief; however, many patients need colectomy, a surgical procedure to remove whole or part of the colon. Though various types of pharmacological agents have been employed for the management of UC, the lack of effectiveness is usually predisposed to various reasons including lack of target-specific delivery of drugs and insufficient drug accumulation at the target site. To overcome these glitches, many researchers have designed and characterized various types of versatile polymeric biomaterials to achieve target-specific delivery of drugs via oral route to optimize their targeting efficiency to the colon, to improve drug accumulation at the target site, as well as to ameliorate off-target effects of chemotherapy. Therefore, the aim of this review was to summarize and critically discuss the pharmaceutical significance and therapeutic feasibility of a wide range of natural and synthetic biomaterials for efficient drug targeting to colon and rationalized treatment of UC. Among various types of biomaterials, natural and synthetic polymer-based hydrogels have shown promising targeting potential due to their innate pH responsiveness, sustained and controlled release characteristics, and microbial degradation in the colon to release the encapsulated drug moieties. These characteristic features make natural and synthetic polymer-based hydrogels superior to conventional pharmacological strategies for the management of UC.

Delivery of anti-inflammatory peptides from hollow PEGylated poly(NIPAM) nanoparticles reduces inflammation in an ex vivo osteoarthritis model

Targeted delivery of anti-inflammatory osteoarthritis treatments have the potential to significantly decrease undesirable systemic side effects and reduce required therapeutic dosage. Here we present a targeted, non-invasive drug delivery system to decrease inflammation in an osteoarthritis model. Hollow thermoresponsive poly(N-isopropylacrylamide) (pNIPAM) nanoparticles have been synthesized via degradation of a N,N'-bis(acryloyl)cystamine (BAC) cross-linked core out of a non-degradable pNIPAM shell. Sulfated 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) was copolymerized in the shell to increase passive loading of an anti-inflammatory mitogen-activated protein kinase-activated protein kinase 2 (MK2)-inhibiting cell-penetrating peptide (KAFAK). The drug-loaded hollow nanoparticles were effective at delivering a therapeutically active dose of KAFAK to bovine cartilage explants, suppressing pro-inflammatory interleukin-6 (IL-6) expression after interleukin-1 beta (IL-1β) stimulation. This thermosensitive hollow nanoparticle system provides an excellent platform for the delivery of peptide therapeutics into highly proteolytic environments such as osteoarthritis.

Collagen-binding nanoparticles for extracellular anti-inflammatory peptide delivery decrease platelet activation, promote endothelial migration, and suppress inflammation

Peripheral artery disease is an atherosclerotic stenosis in the peripheral vasculature that is typically treated via percutaneous transluminal angioplasty. Deployment of the angioplasty balloon damages the endothelial layer, exposing the underlying collagen and allowing for the binding and activation of circulating platelets which initiate an inflammatory cascade leading to eventual restenosis. Here, we report on collagen-binding sulfated poly(N-isopropylacrylamide) nanoparticles that are able to target to the denuded endothelium. Once bound, these nanoparticles present a barrier that reduces cellular and platelet adhesion to the collagenous surface by 67% in whole blood and 59% in platelet-rich plasma under biologically relevant shear rates. In vitro studies indicate that the collagen-binding nanoparticles are able to load and release therapeutic quantities of anti-inflammatory peptides, with the particles reducing inflammation in endothelial and smooth muscle cells by 30% and 40% respectively. Once bound to collagen, the nanoparticles increased endothelial migration while avoiding uptake by smooth muscle cells, indicating that they may promote regeneration of the damaged endothelium while remaining anchored to the collagenous matrix and locally releasing anti-inflammatory peptides into the injured area. Combined, these collagen-binding nanoparticles have the potential to reduce inflammation, and the subsequent restenosis, while simultaneously promoting endothelial regeneration following balloon angioplasty.

STATEMENT OF SIGNIFICANCE

In this manuscript, we present our work on the development and characterization of a novel temperature sensitive collagen-binding nanoparticle system. We demonstrate that when bound to a collagenous matrix, the nanoparticles are able to promote endothelial migration while avoiding cellular uptake. We also show that the nanoparticles are able to reduce inflammation via the release of anti-inflammatory peptides which, when combined with its ability to inhibit platelet binding, could lead to reduced intimal hyperplasia following balloon angioplasty. The drug delivery platform presented represents a unique dual therapy biomaterial wherein the nanoparticle itself plays a crucial role in the system's overall therapeutic potential while simultaneously releasing anti-inflammatory peptides.

Controlled release of anti-inflammatory peptides from reducible thermosensitive nanoparticles suppresses cartilage inflammation

Characterized by pain, cartilage degradation, and inflammation, osteoarthritis is often treated with anti-inflammatory therapies that provide short-term relief but can have adverse side effects; intra-articular drug delivery systems with controlled release of anti-inflammatory peptides using degradable poly(N-isopropylacrylamide) (pNIPAM) nanoparticles could prolong relief and minimize these side effects. Nanoparticles provide a biocompatible drug carrier that can protect encapsulated therapeutics from enzymatic degradation and increase payload delivery upon encountering a degradation stimulus. Here we demonstrate passive targeting of inflamed cartilage ex vivo by uptake of PEGylated pNIPAM nanoparticles with degradable disulfide crosslinks (abbreviated as NGPEGSS) into chondrocytes and subsequent intracellular release of an anti-inflammatory peptide KAFAKLAARLYRKALARQLGVAA (KAFAK). The KAFAK-loaded NGPEGSS treatment reduced ex vivo inflammation to a greater extent compared to its non-degradable counterparts. This study highlights a nanoparticle system that delivers therapeutics intracellularly with improved efficacy by triggered degradation and suppresses inflammation in multiple cell types within an inflamed joint.

Prospects of the practical use of nanoparticles in dermatology

The review presents data from foreign literature sources on the problem of using nanoparticles for theranostics of skin diseases. The article examines properties and operating principles of nanomaterials used most frequently for drug encapsulation and emphasizes advantages of such systems for the treatment of different dermatoses. The need in further exploration of this subject due to underinvestigated adverse events caused by nanoparticles is discussed.

Prevention of Collagen-Induced Platelet Binding and Activation by Thermosensitive Nanoparticles

Peripheral artery disease is an atherosclerotic occlusion in the peripheral vasculature that is typically treated via percutaneous transluminal angioplasty. Unfortunately, deployment of the angioplasty balloon damages the endothelial layer, exposing the underlying collagen and allowing for the binding and activation of circulating platelets, which initiate an inflammatory cascade leading to eventual restenosis. Here, we report on the development of poly(NIPAm-MBA-AMPS-AAc) nanoparticles that have a collagen I-binding peptide crosslinked to their surface allowing them to bind to exposed collagen. Once bound, these particles mask the exposed collagen from circulating platelets, effectively reducing collagen-mediated platelet activation. Using collagen I-coated plates, we demonstrate that these particles are able to bind to collagen at concentrations above 0.5 mg/mL. Once bound, these particles inhibit collagen-mediated platelet activation by over 60%. Using light scattering and zeta potential measurements, we investigated the potential of the nanoparticles as a drug delivery platform. We have verified that the collagen-binding nanoparticles retain the temperature sensitivity common to poly(NIPAm)-based nanoparticles while remaining colloidally stable in aqueous environments. We also demonstrate that they are able to passively load and release anti-inflammatory cell penetrating peptides. Combined, we have developed a collagen-binding nanoparticle that has dual therapy potential, preventing collagen-mediated platelet activation while delivering water-soluble therapeutics directly to the damaged area.

A biodegradable and fluorescent nanovehicle with enhanced selective uptake by tumor cells

The tumor-targeted drug delivery system, DOX@LA-pDAGEA/pPEGA-b-p(DMDEA-co-BADS), with reduction- and pH-dependent degradation and fluorescence imaging function displayed an enhanced anticancer effect.