Superiority of a Silk Surgical Site Wound Closure Device over Synthetic Dressings.

Background: Silk fibroin is an emerging biomaterial with enhanced properties of cellular regeneration, growth, and proliferation. The use of a silk fibroin wound dressing has the potential to decrease the incidence of wound-healing complications and to improve patient outcomes compared with synthetic dressing alternatives.

Methods: A randomized, single-blind clinical trial was conducted on 50 patients who were dressed with a silk fibroin dressing on 1 side of their body and 3M Steri-Strips on the contralateral side after abdominoplasty, reduction mammaplasty, or brachioplasty procedures.

Silk Bioprotein as a Novel Surgical-Site Wound Dressing: A Prospective, Randomized, Single-Blinded, Superiority Clinical Trial.

Background: Medical adhesive-related skin injuries (MARSIs) affect about 1.5 million patients annually in the United States. Complications include allergic contact dermatitis, skin blistering, skin tears, and surgical-site infections (SSIs).

Recent progress of redox-responsive polymeric nanomaterials for controlled release.

Redox-responsive polymeric nanomaterials (PNMs) have been attractive research targets for drug delivery systems because disturbed levels of redox molecules are associated with the progression of various diseases. To enable PNMs to target biorelevant redox molecules, including reactive oxygen species (ROS), glutathione (GSH) and hydrogen sulfide (H2S), appropriate responsive moieties have to be installed within the polymer structure. Upon application of redox stimuli, redox-responsive PNMs undergo structural changes to release encapsulated payloads.

Highly responsive and rapid hydrogen peroxide-triggered degradation of polycaprolactone nanoparticles.

We synthesized an oxidation-responsive polycaprolactone (O-PCL) bearing pendant arylboronic esters as H2O2-responsive motifs. H2O2 induces fast depolymerization of O-PCL within days. Nanoparticles formulated from O-PCL disintegrate and release payload in response to concentrations of H2O2 (50 μM) that are relevant to human disease.

The Chemistry of Boronic Acids in Nanomaterials for Drug Delivery.

Interest in increasing drug delivery efficiency has risen over the past decade both as a means to improve efficacy of already clinically available drugs and due to the increased difficulties of approving new drugs. As a functional group for targeted drug delivery, boronic acids (BAs) have been incorporated in polymeric particles both as a stimuli-responsive functional group and as a targeting ligand. Here, BA chemistry presents a wealth of opportunities for biological applications.

A Bioelectronic Platform Modulates pH in Biologically Relevant Conditions.

Bioelectronic devices that modulate pH can affect critical biological processes including enzymatic activity, oxidative phosphorylation, and neuronal excitability. A major challenge in controlling pH is the high buffering capacity of many biological media. To overcome this challenge, devices need to be able to store and deliver a large number of protons on demand.

Inflammation-Responsive Drug-Conjugated Dextran Nanoparticles Enhance Anti-Inflammatory Drug Efficacy.

Stimuli-responsive nanoparticles (NPs) are especially interesting to enhance the drug delivery specificity for biomedical applications. With the aim to achieve a highly stable and inflammation-specific drug release, we designed a reactive oxygen species (ROS)-responsive dextran-drug conjugate (Nap-Dex). By blending Nap-Dex with the acid-sensitive acetalated dextran polymer, we achieved a dual-responsive NP with high specificity toward the inflammatory environment.

Disease-Triggered Drug Release Effectively Prevents Acute Inflammatory Flare-Ups, Achieving Reduced Dosing.

For conditions with inflammatory flare-ups, fast drug-release from a depot is crucial to reduce cell infiltration and prevent long-term tissue destruction. While this concept has been explored for chronic diseases, preventing acute inflammatory flares has not been explored. To address this issue, a preventative inflammation-sensitive system is developed and applied to acute gout, a condition where millions of inflammatory cells are recruited rapidly, causing excruciating and debilitating pain.

Delivery of Cargo with a Bioelectronic Trigger.

Biological systems exchange information often with chemical signals. Here, we demonstrate the chemical delivery of a fluorescent label using a bioelectronic trigger. Acid-sensitive microparticles release fluorescin diacetate upon low pH induced by a bioelectronic device.

A Single-Blind Study Evaluating the Efficacy of Gold Nanoparticle Photothermal-Assisted Liposuction in an Ex Vivo Human Tissue Model.

Background: Liposuction is one of the most performed cosmetic surgery procedures. In a previously reported study, gold-nanoparticle (GNP) laser-assisted liposuction (NanoLipo) was shown to improve procedure parameters and outcomes in a porcine model.

Objectives: An ex vivo human liposuction model was developed to assess the ease, efficacy, and outcomes of NanoLipo, and to further explore its mechanism of action in facilitating liposuction.

Chemical amplification accelerates reactive oxygen species triggered polymeric degradation.

Chemical amplification is a known strategy for improving the sensitivity of stimuli-responsive polymers. However, the chemical amplification effect has never been fully examined. Many questions remain about its mechanism and efficacy, obstructing its further implementation.

Review of the progress toward achieving heat confinement-the holy grail of photothermal therapy.

Photothermal therapy (PTT) involves the application of normally benign light wavelengths in combination with efficient photothermal (PT) agents that convert the absorbed light to heat to ablate selected cancers. The major challenge in PTT is the ability to confine heating and thus direct cellular death to precisely where PT agents are located. The dominant strategy in the field has been to create large libraries of PT agents with increased absorption capabilities and to enhance their delivery and accumulation to achieve sufficiently high concentrations in the tissue targets of interest.

Simultaneous Enhancement of Photoluminescence, MRI Relaxivity, and CT Contrast by Tuning the Interfacial Layer of Lanthanide Heteroepitaxial Nanoparticles.

Nanoparticle (NP) based exogenous contrast agents assist biomedical imaging by enhancing the target visibility against the background. However, it is challenging to design a single type of contrast agents that are simultaneously suitable for various imaging modalities. The simple integration of different components into a single NP contrast agent does not guarantee the optimized properties of each individual components.

Distinct ON/OFF fluorescence signals from dual-responsive activatable nanoprobes allows detection of inflammation with improved contrast.

Visualization of biochemical changes associated with disease is of great clinical significance, as it should allow earlier, more accurate diagnosis than structural imaging, facilitating timely clinical intervention. Herein, we report combining stimuli-responsive polymers and near-infrared fluorescent dyes (emission max: 790 nm) to create robust activatable fluorescent nanoprobes capable of simultaneously detecting acidosis and oxidative stress associated with inflammatory microenvironments. The spectrally-resolved mechanism of fluorescence activation allows removal of unwanted background signal (up to 20-fold reduction) and isolation of a pure activated signal, which enables sensitive and unambiguous localization of inflamed areas; target-to-background ratios reach 22 as early as 3 h post-injection.

Direct Evidence for Coupled Surface and Concentration Quenching Dynamics in Lanthanide-Doped Nanocrystals.

Luminescence quenching at high dopant concentrations generally limits the dopant concentration to less than 1-5 mol% in lanthanide-doped materials, and this remains a major obstacle in designing materials with enhanced efficiency/brightness. In this work, we provide direct evidence that the major quenching process at high dopant concentrations is the energy migration to the surface (i.e.

Biorthogonal click chemistry on poly(lactic-co-glycolic acid)-polymeric particles.

Biodegradable polymeric materials are a key area of investigation in drug delivery and disease treatment. This is due to their proven clinical potential for payload protection, responsivity, and surface modification imparted by the versatile array of polymers available for their formulation. Here, we employ a novel biodegradable azide containing polymer in the formulation of polymeric nanoparticles and show that these particles can then be functionalized, with biorthogonal click reactions, to alter their surface appearance and their ability to interact with biological systems.

Compact Micellization: A Strategy for Ultrahigh T1 Magnetic Resonance Contrast with Gadolinium-Based Nanocrystals.

Paramagnetic gadolinium (Gd(3+))-based nanocrystals (NCs) with a large number of confined gadolinium ions can be expected to heavily enhance the longitudinal (T1) relaxation of water protons compared to clinical gadolinium complexes with only a single paramagnetic center. However, paramagnetic Gd(3+)-NCs reported to date show only a modest T1 relaxivity of ∼10 mM(-1) s(-1) per Gd(3+) at 1.5 T, only about 3-times higher than clinical Gd(3+) complexes.

Enhanced UV upconversion emission using plasmonic nanocavities.

Upconversion of near infrared (NIR) into ultraviolet (UV) radiation could lead to a number of applications in bio-imaging, diagnostics and drug delivery. However, for bare nanoparticles, the conversion efficiency is extremely low. In this work, we experimentally demonstrate strongly enhanced upconversion emission from an ensemble of β-NaYF:Gd/Yb/Tm @NaLuF core-shell nanoparticles trapped in judiciously designed plasmonic nanocavities.

Nanogels as imaging agents for modalities spanning the electromagnetic spectrum.

In the past few decades, advances in imaging equipment and protocols have expanded the role of imaging in diagnosis and disease management, especially in cancer. Traditional imaging agents have rapid clearance and low specificity for disease detection. To improve accuracy in disease identification, localization and assessment, novel nanomaterials are frequently explored as imaging agents to achieve high detection specificity and sensitivity.

Efficient Red Light Photo-Uncaging of Active Molecules in Water Upon Assembly into Nanoparticles.

We introduce a means of efficiently photo-uncaging active compounds from amino-1,4-benzoquinone in aqueous environments. Aqueous photochemistry of this photocage with one-photon red light is typically not efficient unless the photocaged molecules are allowed to assemble into nanoparticles. A variety of biologically active molecules were functionalized with the photocage and subsequently formulated into water-dispersible nanoparticles.

Layered hydrogels accelerate iPSC-derived neuronal maturation and reveal migration defects caused by MeCP2 dysfunction.

Probing a wide range of cellular phenotypes in neurodevelopmental disorders using patient-derived neural progenitor cells (NPCs) can be facilitated by 3D assays, as 2D systems cannot entirely recapitulate the arrangement of cells in the brain. Here, we developed a previously unidentified 3D migration and differentiation assay in layered hydrogels to examine how these processes are affected in neurodevelopmental disorders, such as Rett syndrome. Our soft 3D system mimics the brain environment and accelerates maturation of neurons from human induced pluripotent stem cell (iPSC)-derived NPCs, yielding electrophysiologically active neurons within just 3 wk.

Degradable acetalated dextran microparticles for tunable release of an engineered hepatocyte growth factor fragment.

Injectable biomaterials are promising as new therapies to treat myocardial infarction (MI). One useful property of biomaterials is the ability to protect and sustain release of therapeutic payloads. In order to create a platform for optimizing the release rate of cardioprotective molecules we utilized the tunable degradation of acetalated dextran (AcDex).

Haptotaxis is cell type specific and limited by substrate adhesiveness.

Motile cells navigate through tissue by relying on tactile cues from gradients provided by extracellular matrix (ECM) such as ligand density or stiffness. Mesenchymal stem cells (MSCs) and fibroblasts encounter adhesive or 'haptotactic' gradients at the interface between healthy and fibrotic tissue as they migrate towards an injury site. Mimicking this phenomenon, we developed tunable RGD and collagen gradients in polyacrylamide hydrogels of physiologically relevant stiffness using density gradient multilayer polymerization (DGMP) to better understand how such ligand gradients regulate migratory behaviors.

Light-triggered chemical amplification to accelerate degradation and release from polymeric particles.

We describe a means of chemical amplification to accelerate triggered degradation of a polymer and particles composed thereof. We designed a light-degradable copolymer containing carboxylic acids masked by photolabile groups and ketals. Photolysis allows the unmasked acidic groups in the polymer backbone to accelerate ketal hydrolysis even at neutral pH.

Photocontrolled release using one-photon absorption of visible or NIR light.

Light is an excellent means to externally control the properties of materials and small molecules for many applications. Light's ability to initiate chemistries largely independent of a material's local environment makes it particularly useful as a bio-orthogonal and on-demand trigger in living systems. Materials responsive to UV light are widely reported in the literature; however, UV light has substantial limitations for in vitro and in vivo applications.