Toward a disruptive, minimally invasive small finger joint implant concept: Cellular and molecular interactions with materials in vivo.

Osteoarthritis (OA) poses significant therapeutic challenges, particularly OA that affects the hand. Currently available treatment strategies are often limited in terms of their efficacy in managing pain, regulating invasiveness, and restoring joint function. The APRICOT implant system developed by Aurora Medical Ltd (Chichester, UK) introduces a minimally invasive, bone-conserving approach for treating hand OA (https://apricot-project.

Fabrication and Characterization of Mucin Nanoparticles for Drug Delivery Applications.

Mucin glycoproteins are ideal biomacromolecules for drug delivery applications since they naturally offer a plethora of different functional groups that can engage in specific and unspecific binding interactions with cargo molecules. However, to fabricate drug carrier objects from mucins, suitable stabilization mechanisms have to be implemented into the nanoparticle preparation procedure that allow for drug release profiles that match the requirements of the selected cargo molecule and its particular mode of action. Here, we describe two different methods to prepare crosslinked mucin nanoparticles that can release their cargo either on-demand or in a sustained manner.

A pH-stable, mucin based nanoparticle system for the co-delivery of hydrophobic and hydrophilic drugs.

Biopolymer-based drug carriers are commonly used for the development of safe delivery systems. However, biopolymer-based systems are often highly sensitive to the acidic pH levels in the stomach and release most of their cargo before they have reached their point of destination. Such premature drug release combined with the resulting high dose requirements is not cost-efficient and comes with the risk of unwanted side effects on non-target tissues/organs.

Bio-based and bio-inspired adhesives from animals and plants for biomedical applications.

With the "many-headed" slime mold having been voted the unicellular organism of the year 2021 by the German Society of Protozoology, we are reminded that a large part of nature's huge variety of life forms is easily overlooked - both by the general public and researchers alike. Indeed, whereas several animals such as mussels or spiders have already inspired many scientists to create novel materials with glue-like properties, there is much more to discover in the flora and fauna. Here, we provide an overview of naturally occurring slimy substances with adhesive properties and categorize them in terms of the main chemical motifs that convey their stickiness, , carbohydrate-, protein-, and glycoprotein-based biological glues.

Emulsions of hydrolyzable oils for the zero-order release of hydrophobic drugs.

Drug delivery systems that release hydrophobic drugs with zero-order kinetics remain rare and are often complicated to use. In this work, we present a gellified emulsion (emulgel) that comprises oil droplets of a hydrolyzable oil entrapped in a hydrogel. In the oil, we incorporate various hydrophobic drugs and, because the oil hydrolyzes with zero-order kinetics, the release of the drugs is also linear.

Repulsive Backbone-Backbone Interactions Modulate Access to Specific and Unspecific Binding Sites on Surface-Bound Mucins.

Mucin glycoproteins are the matrix-forming key components of mucus, the innate protective barrier protecting us from pathogenic attack. However, this barrier is constantly challenged by mucin-degrading enzymes, which tend to target anionic glycan chains such as sulfate groups and sialic acid residues. Here, we demonstrate that the efficiency of both unspecific and specific binding of small molecules to mucins is reduced when sulfate groups are enzymatically removed from mucins; this is unexpected because neither of the specific mucin-binding partners tested here targets these sulfate motifs on the mucin glycoprotein.

Bioinspired Dopamine/Mucin Coatings Provide Lubricity, Wear Protection, and Cell-Repellent Properties for Medical Applications.

Even though medical devices have improved a lot over the past decades, there are still issues regarding their anti-biofouling properties and tribological performance, and both aspects contribute to the short- and long-term failure of these devices. Coating these devices with a biocompatible layer that reduces friction, wear, and biofouling at the same time would be a promising strategy to address these issues. Inspired by the adhesion mechanism employed by mussels, here, dopamine is made use of to immobilize lubricious mucin macromolecules onto both manufactured commercial materials and real medical devices.

DNA Strands Trigger the Intracellular Release of Drugs from Mucin-Based Nanocarriers.

Gaining control over the delivery of therapeutics to a specific disease site is still very challenging. However, especially when cytotoxic drugs such as chemotherapeutics are used, the importance of a control mechanism that can differentiate "sick" target cells from the surrounding healthy tissue is pivotal. Here, we designed a nanoparticle-based drug delivery process, which releases an active agent only in the presence of a specific trigger DNA sequence.

Several Sterilization Strategies Maintain the Functionality of Mucin Glycoproteins.

Mucin glycoproteins, the macromolecular components of mucus, combine a broad range of biomedically important properties. Among those is the ability of mucin solutions to act as excellent lubricants. However, to be able to use purified, endogenous mucin glycoproteins as components of a biomedical product, the mucins need to be sterile; this, in turn, makes it necessary to subject the mucins to quite harsh physical treatments, such as heat exposure, autoclaving, UV-, or γ-irradiation, which might compromise the functionality of the glycoproteins.

Charged glycan residues critically contribute to the adsorption and lubricity of mucins.

In the human body, mucin glycoproteins efficiently reduce friction between tissues and thereby protect the mucosa from mechanical damage. Mucin lubricity is closely related to their molecular structure: it has been demonstrated previously that the hydrophobic termini of mucins critically contribute to their lubricity. If and how intrinsic sources of negative charge in mucins, e.

Pentacene Excitons in Strong Electric Fields.

Electroluminescence spectroscopy of organic semiconductors in the junction of a scanning tunneling microscope (STM) provides access to the polarizability of neutral excited states in a well-characterized molecular geometry. We study the Stark shift of the self-trapped lowest singlet exciton at 1.6 eV in a pentacene nanocrystal.

Dynamic control of plasmon generation by an individual quantum system.

Controlling light on the nanoscale in a similar way as electric currents has the potential to revolutionize the exchange and processing of information. Although light can be guided on this scale by coupling it to plasmons, that is, collective electron oscillations in metals, their local electronic control remains a challenge. Here, we demonstrate that an individual quantum system is able to dynamically gate the electrical plasmon generation.

Molecular orbital gates for plasmon excitation.

Future combinations of plasmonics with nanometer-sized electronic circuits require strategies to control the electrical excitation of plasmons at the length scale of individual molecules. A unique tool to study the electrical plasmon excitation with ultimate resolution is scanning tunneling microscopy (STM). Inelastic tunnel processes generate plasmons in the tunnel gap that partially radiate into the far field where they are detectable as photons.

Crystalline inverted membranes grown on surfaces by electrospray ion beam deposition in vacuum.

Crystalline inverted membranes of the nonvolatile surfactant sodium dodecylsulfate are found on solid surfaces after electrospray ion beam deposition (ES-IBD) of large SDS clusters in vacuum. This demonstrates the equivalence of ES-IBD to conventional molecular beam epitaxy.

Scanning tunneling luminescence of individual CdSe nanowires.

The local luminescence properties of individual CdSe nanowires composed of segments of zinc blende and wurtzite crystal structures are investigated by low-temperature scanning tunneling luminescence spectroscopy. Light emission from the wires is achieved by the direct injection of holes and electrons, without the need for coupling to tip-induced plasmons in the underlying metal substrate. The photon energy is found to increase with decreasing wire diameter due to exciton confinement.

Substrate effect on supramolecular self-assembly: from semiconductors to metals.

Terephthalic acid (TPA) deposited on Si(111)-7 x 7, Si(111)-square root 3 x square root 3-Ag and Ag(111) has been studied as a model system to understand how much passivated semiconductor surfaces differ from semiconductor and metal surfaces in respect of supramolecular self assembly. By scanning tunneling microscopy it is found that TPA molecules do not form any ordered supramolecular structure on the pristine semiconductor surface, due to a strong molecule-substrate interaction. On the contrary, TPA has a weaker interaction with Si(111)-square root 3 x square root 3-Ag, leading to the formation of an ordered supramolecular layer stabilized by carboxyl hydrogen bonds.