Kelvin Yeung

• PhD (Medicine), MPhil (Medicine), BSc., MHKIE
• Ng Chun-Man Professor in Orthopaedic Bioengineering at The University of Hong Kong

Antibiotic therapy is a key strategy for treating infections associated with orthopedic implants, yet its limited effectiveness and potential to disrupt bone healing highlight the need for innovative approaches. Herein, a TiO2‐Graphene (TiO2‐G) metastructure is developed on Ti implant surface using a hydrothermal method coupled with plasma‐enhanced...

Early osteoimmune microenvironment disorder at the interface between bone and implant can lead to implant loosening, which prolongs patient convalescence, exacerbates postoperative complications, and potentially results in implant failure. The timely regulation of macrophages primarily orchestrates the entire long‐term regeneration process. Here, i...

Age-related osteoporosis is a metabolic skeletal disorder caused by estrogen deficiency in postmenopausal women. Prolonged use of anti-osteoporotic drugs such as bisphosphonates and FDA-approved anti-resorptive selective estrogen receptor modulators (SERMs) has been associated with various clinical drawbacks. We recently discovered a low-molecular-...

Infection and poor tissue repair are the key causes of percutaneous implantation failure. However, there is a lack of effective strategies to cope with due to its high requirements of sterilization, soft tissue healing, and osseointegration. In this work, l-arginine (L-Arg) was loaded onto a sulfonated polyetheretherketone (PEEK) surface to solve t...

Achieving bacterial killing and osteogenic formation on an implant surface rarely occurs. In this study, a novel surface design–a palladium hydride (PdHx) film that enables these two distinct features to coexist is introduced. The PdHx lattice captures protons in the extracellular microenvironment of bacteria, disrupting their normal metabolic acti...

Excessive bone marrow adipocytes (BMAds) accumulation often occurs under diverse pathophysiological conditions associated with bone deterioration. Estrogen-related receptor α (ESRRA) is a key regulator responding to metabolic stress. Here, we show that adipocyte-specific ESRRA deficiency preserves osteogenesis and vascular formation in adipocyte-ri...

Deep burns lead to extensive damage to the dermal layer, necessitating a longer treatment duration than typical skin injuries. Such burn wounds become more susceptible to drug‐resistant bacterial infections, thereby complicating and prolonging the therapeutic process. In this study, a unique spray composed of covalent metal hybrid‐linked organic fr...

Ectopic bone marrow adipocytes (BMAds) accumulation occurring under diverse pathophysiological conditions leads to bone deterioration. Estrogen-related receptor α (ESRRA) is a key regulator responding to metabolic stress. Here, we show that adipocyte-specific ESRRA deficiency rescues osteogenesis and vascular formation in adipocyte-rich bone marrow...

Correction for 'Construction of perfluorohexane/IR780@liposome coating on Ti for rapid bacteria killing under permeable near infrared light' by Xiuhua Wang et al., Biomater. Sci., 2018, 6, 2460-2471, https://doi.org/10.1039/C8BM00602D.

There is an evident advantage in personalized customization of orthopedic implants by 3D-printed titanium (Ti) and its alloys. However, 3D-printed Ti alloys have a rough surface structure caused by adhesion powders and a relatively bioinert surface. Therefore, surface modification techniques are needed to improve the biocompatibility of 3D-printed...

With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterials. Decellularized extracellular matrix (dECM) has been extensively used in the clinical treatment of tissue injury due to its favorab...

Acne is an inflammatory skin disease mainly caused by Propionibacterium acnes, which can cause local inflammatory reactions and develop into chronic inflammatory diseases in severe cases. To avoid the use of antibiotics and to effectively treat the site of acne, we report a sodium hyaluronate microneedle patch that mediates the transdermal delivery...

It is important to eliminate lipopolysaccharide (LPS) along with killing bacteria in periprosthetic joint infection (PJI) therapy for promoting bone repair due to its effect to regulate macrophages response. Although natural antimicrobial peptides (AMPs) offer a good solution, the unknown toxicity, high cost and exogenetic immune response hamper th...

[This corrects the article DOI: 10.1016/j.bioactmat.2021.07.030.].

[This corrects the article DOI: 10.1016/j.bioactmat.2021.08.027.].

Leaf Veins The leaf vein is the “vascular system” in plants. In article 2201220 by Kelvin W. K. Yeung, Xin Zhao, and co‐workers, a leaf‐vein micropattern is engraved on a PGLADMA polymer membrane, serving as “running tracks” for vascular endothelial cells to facilitate hierarchical and functional vascular reconstruction. The leaf‐vein engraved memb...

Conferring catalytic defects in sonosensitizers is of paramount importance in reinforcing sonodynamic therapy. However, the formation of such zero‐dimensional (0D) defects is governed by the Schottky defect principle. We herein design two‐dimensional (2D) catalytic planar defects within Ti3C2 sheets to address this challenge. These specific planar...

Intelligent control of the immune response is essential for obtaining percutaneous implants with good sterilization and tissue repair abilities. In this study, polypyrrole (Ppy) nanoparticles enveloping a 3D frame of sulfonated polyether ether ketone (SP) surface are constructed, which enhance the surface modulus and hardness of the sulfonated laye...

Hierarchical vasculature reconstruction is fundamental for tissue regeneration. The regeneration of functional vascular network requires a proper directional guidance, especially in case of large‐size defects. To provide the “running track” for vasculature, a leaf‐vein mimetic membrane using soft and elastic poly(lactide‐co‐propylene glycol‐co‐lact...

Bio-implants are widely used in clinic for repair defected bone, however, clinical trace always found that the poor osseointegration often results in bone repair failure. In this study, we investigated whether simvastatin loaded onto sulfonated PEEK (SP) surfaces enhances the bone formation effect of the SP samples. Our results showed that simvasta...

While conventional bacterial pneumonia mainly centralizes avoidance of bacterial colonization, it remains unclear how to restore the host immunity for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia. Here, probiotic-based nanoparticles of OASCLR were formed by coating chitosan, hyaluronic acid, and ononin on...

The healing of critical-sized bone defects (CSD) remains a challenge in orthopaedic medicine. In recent years, scaffolds with sophisticated microstructures fabricated by the emerging three-dimensional (3D) printing technology have lighted up the treatment of the CSD due to the elaborate microenvironments and support they may build. Here, we establi...

Owing to the existence of the outer membrane barrier, most antibacterial agents cannot penetrate Gram-negative bacteria and are ineffective. Here, we report a general method for narrow-spectrum antibacterial Garcinia nanoparticles that can only be effective to kill Gram-positive bacteria, to effectively eliminate Gram-negative bacteria by creating...

Multidrug‐resistant (MDR) bacteria are emerging and disseminating rapidly, undoubtedly posing an urgent threat to global public health. One particular concern is that MDR Gram‐negative bacteria are immunized to available antibiotics owing to a series of biogenetic effects, including the β‐barrel assembly machine (BAM complex) in the outer membrane,...

[This corrects the article DOI: 10.3389/fbioe.2021.803723.].

Background Exosomes derived from stem cells have been widely studied for promoting regeneration and reconstruction of multiple tissues as “cell-free” therapies. However, the applications of exosomes have been hindered by limited sources and insufficient therapeutic potency. Results In this study, a stem cell-mediated gene therapy strategy is devel...

Biogenic collagen membranes have been widely used as soft tissue barriers in guided bone regeneration (GBR) and guided tissue regeneration (GTR). Nevertheless, their clinical performance remains unsatisfactory because of their low mechanical strength and fast degradation rate in vivo. Although cross-linking with chemical agents is effective and rel...

Alternative antimicrobials are urgently needed due to the antibiotic resistance. Herein, vertical graphene has been in-situ prepared on medical titanium ([email protected]) by plasma-enhanced chemical vapor deposition for rapid sterilization under near-infrared light. The physicochemical properties, photothermal effect, antibacterial activity, and...

Bone formation induced by divalent metal cations has been widely reported; however, the underlying mechanism is unclear. Here we report that these cations stimulate skeleton interoception by promoting prostaglandin E2 secretion from macrophages. This immune response is accompanied by the sprouting and arborization of calcitonin gene-related polypep...

Bone grafts are commonly used for the treatment of critical sized bone defects. Since the supply of autologous bone is insufficient, allogeneic bone grafts have been used most of the time. However, the poor osteogenic property of allogeneic bone grafts after pretreatment results in delayed union, non-union, or even occasional deformity. Calcium pho...

β-lactamase, a kind of hydrolase in multi-drug resistant pathogens, can hydrolyze β-lactam antibiotics and make these kinds of antibiotics invalid. Small-molecular inhibitors about the enzyme and their mechanism are widely investigated but they may result in unavoidable adverse reactions and drug-resistance. Herein, we propose a new therapeutic str...

The most critical factor determining the success of biodegradable bone implants is the host tissue response, which greatly depends on their degradation behaviors. Here, a new magnesium‐based implant, namely magnesium–silicon–calcium (Mg–0.2Si–1.0Ca) alloy, that coordinates its biodegradation along with the bone regenerative process via a self‐assem...

The effects of dual Zr and O plasma immersion ion implantation (Zr & O PIII) on antibacterial properties of ZK60 Mg alloys are systematically investigated. The results show that a hydrophobic, smooth, and ZrO2-containing graded film is formed. Electrochemical assessment shows that the corrosion rate of the plasma-treated Mg alloy decreases and the...

Regardless of the advancement of synthetic bone substitutes, allograft-derived bone substitutes still dominate in the orthopaedic circle in the treatments of bone diseases. Nevertheless, the stringent devitalization process jeopardizes their osseointegration with host bone and therefore prone to long-term failure. Hence, improving osseointegration...

Although efforts have been devoted to develop new antibacterial agents and techniques, the challenge of bacterial infection remains unresolved and is even increasing. Sonodynamic therapy (SDT) driven by ultrasound (US) has demonstrated effectiveness in terms of penetration and it can help to clinically address the problem of deep tissue bacterial i...

Extrapulmonary complications of different organ systems have been increasingly recognized in patients with severe or chronic Coronavirus Disease 2019 (COVID-19). However, limited information on the skeletal complications of COVID-19 is known, even though inflammatory diseases of the respiratory tract have been known to perturb bone metabolism and c...

The design of orthopedic biomaterials has gradually shifted from “immune-friendly” to “immunomodulatory,” in which the biomaterials are able to modulate the inflammatory response via macrophage polarization in a local immune microenvironment that favors osteogenesis and implant-to-bone osseointegration. Despite the well-known effects of bioactive m...

The potential translation of bio-inert polymer scaffolds as bone substitutes is limited by the lack of neovascularization upon implantation and subsequently diminished ingrowth of host bone, most likely resulted from the inability to replicate appropriate endogenous crosstalk between cells. Human umbilical vein endothelial cell-derived decellulariz...

Bone formation induced by divalent metal cations has been widely reported; however, the underlying mechanism is unclear. Here we report that these cations stimulate skeleton interoception by promoting prostaglandin E2 (PGE 2 ) secretion from macrophages. This imune response is accompanied by the sprouting and arborization of calcitonin gene-related...

Clinically, lethal viral-bacterial pneumonia is a severe threat to human health worldwide. Here, for the first time, we propose a “material-herbology” strategy, in which herbal medicines are utilized as materials or refreshed by using materialogy methods to enhance their therapeutic effect. Specifically, in this work, natural tea nanodots (TNDs, wi...

Macrophage has been gradually recognized as a central regulator in tissue regeneration, and the study of how macrophage mediates biomaterials-induced bone regeneration through immunomodulatory pathway becomes popular. However, the current understanding on the roles of different macrophage phenotypes in regulating bone tissue regeneration remains co...

Methicillin‐resistant Staphylococcus aureus (MRSA) biofilm infections after orthopedic implant increase the risk of failure and potentially cause amputation of limbs or life‐threatening sepsis in severe cases. Additionally, satisfactory bone‐implant integration is another important indicator of an ideal implant. Here, an antibiotic‐free antibacteri...

Both phototherapy via photocatalysts and physical puncture by artificial nanostructures are promising substitutes for antibiotics when treating drug-resistant bacterial infectious diseases. However, the photodynamic therapeutic efficacy of photocatalysts is seriously restricted by the rapid recombination of photogenerated electron–hole pairs. Meanw...

Despite the widespread observations on the osteogenic effects of magnesium ion (Mg ²⁺ ), the diverse roles of Mg ²⁺ during bone healing have not been systematically dissected. Here, we reveal a previously unknown, biphasic mode of action of Mg ²⁺ in bone repair. During the early inflammation phase, Mg ²⁺ contributes to an upregulated expression of...

Surface mechanical attrition treatment (SMAT) method is an effective way to generate nanograined (NG) surface on Ti-25Nb-3Mo-2Sn-3Zr (wt.%) (named as TLM), a kind of β-type titanium alloy, and the achieved nanocrystalline surface was proved to promote positive functions of osteoblastic cells. In this work, to further endow the NG TLM alloy with bot...

Proper immune responses are critical for successful biomaterial implantation. Here, four scales of honeycomb-like TiO 2 structures were custom made on titanium (Ti) substrates to investigate cellular behaviors of RAW 264.7 macrophages and their immunomodulation on osteogenesis. We found that the reduced scale of honeycomb-like TiO 2 structures coul...

Some infectious or malignant diseases such as cancers are seriously threatening the health of human beings all over the world. The commonly used antibiotic therapy cannot effectively treat these diseases within a short time, and also bring about adverse effects such as drug resistance and immune system damage during long-term systemic treatment. Ph...

In view of increasing drug resistance, ecofriendly photoelectrical materials are promising alternatives to antibiotics. Here we design an interfacial Schottky junction of Bi2S3/Ti3C2Tx resulting from the contact potential difference between Ti3C2Tx and Bi2S3. The different work functions induce the formation of a local electrophilic/nucleophilic re...

The fate of cells and subsequent bone regeneration is highly correlated with temporospatial coordination of chemical, biological, or physical cues within a local tissue microenvironment. Deeper understanding of how mammalian cells react to local tissue microenvironment is paramount important when designing next generation of biomaterials for tissue...

A PLGA/Ti3C2 hybrid coating was successfully deposited on the surface of magnesium-strontium (Mg-Sr) alloys. Compared with the corrosion current density (i corr ) of the Mg-Sr alloy (7.13 × 10-5 A/cm2), the modified samples (Mg/PLGA/Ti3C2) was lower by approximately four orders of magnitude (7.65 × 10-9 A/cm2). After near infrared 808 nm laser irra...

Rapid bacteria killing and tissue repair are critical for the fast healing of bacteria-infected wounds, especially under poor sanitation without antibiotics. Herein, we prepared a novel xerogel constructed by thioether as a main chain and embedded by Ag nanoparticles (NPs) and ZnO NPs decorated by N-doped carbon dots ([email protected]). This hybri...

Sonodynamic therapy (SDT) is considered to be a potential treatment for various diseases including cancers and bacterial infections due to its deep penetration ability and biosafety, but its SDT efficiency is limited by the hypoxia environment of deep tissues. This study proposes creating a potential solution, sonothermal therapy, by developing the...

Recently, photoactivated sterilization, as a rapid, effective, and antibiotic-free antibacterial method, has attracted increasing attention from researchers. Many outstanding photoresponsive materials, including photocatalysts, photosensitizers (PSs), and photothermal materials, have been developed and applied to microbial inactivation and to treat...

Preventing multidrug-resistant bacteria-related infection and simultaneously improving osseointegration are in great demand for orthopedic implants. However, current strategies are still limited to a combination of non-U.S. Food and Drug Administration-approved antibacterial and osteogenic agents. Here, we develop a food-grade probiotic-modified im...

Owing to the poor penetration depth of light, phototherapy, including photothermal and photodynamic therapies, remains severely ineffective in treating deep tissue infections such as methicillin-resistant Staphylococcus aureus (MRSA)-infected osteomyelitis. Here, we report a microwave-excited antibacterial nanocapturer system for treating deep tiss...

Bacterial infectious diseases and bacterial‐infected environments have been threatening the health of human beings all over the world. In view of the increased bacteria resistance caused by overuse or improper use of antibiotics, antibacterial biomaterials are developed as the substitutes for antibiotics in some cases. Among them, antibacterial hyd...

Injured tissues are susceptible to infections that suppress wound healing. Rapid and safe sterilization is therefore urgent for bacteria-infected wounds, especially under harsh conditions without antibiotic availability. In this work, we developed a photoresponsive metal-organic framework (MOF) heterojunction that responds to 660 nm light irradiati...

High-pressure torsion (HPT) can refine the microstructure and consequently modify the properties, such as mechanical and corrosion properties, of Mg and its alloys. Biodegradable magnesium materials alloyed with the essential elements of life, such as Ca and Sr, are a current research frontier. In this study, biodegradable ultrafine-grained pure Mg...

A light‐inspired hydroxyapatite (Hap)/nitrogen‐doped carbon dots (NCDs) modified graphene oxide (GO) heterojunction film is developed, which shows a promoted separation of interfacial electrons and holes and an inhibited recombination efficiency via hole depletion. The metabolism of bacteria on this film is significantly inhibited under light irrad...

Herein, a metal-organic framework (MOF) was modified using polydopamine (PDA) to develop the MOF-PDA as a photoresponsive bacteria-killing agent under 660 nm light irradiation. The modification using PDA led to the production of not only more heat, but also much more ¹O2. This is because the PDA could interact with the porphyrin ring of the MOF thr...

Implant-associated infections is one of the most challenging post-operative complications in bone-related implantations. To tackle this clinical issue, we developed a low-cost and durable surface coating for medical grade titanium implants that uses positively charged silane molecules. The in vitro antimicrobial tests revealed that the titanium sur...

Clinically, methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection inevitably induces the failure of bone implants. Herein, a hydrophilic and viscous hydrogel of polyvinyl alcohol modified with chitosan, polydopamine, and NO release donor was formed on red phosphorous nanofilm deposited on titanium implant (Ti-RP/PCP/RSNO). Under the...

The abuse of antibiotics is leading to the emergence of resistant bacteria. In this work, a drug-free composite of ZnO/CDots/g-C3N4 with Z-scheme heterojunction was developed, which was employed to kill bacteria effectively within a very short time under the irradiation of visible light due to the enhanced photocatalytic and photothermal effects. I...

The use of magnesium ion (Mg2+)-modified biomaterials in bone regeneration is a promising and cost-effective therapeutic. Despite the widespread observation on the osteogenic effects of Mg2+, the diverse roles played by Mg2+ in the complex biological process of bone healing have not been systematically dissected. Here, we reveal a previously unknow...

Global multidrug‐resistant (MDR) bacteria are spreading rapidly and causing a great threat to human health due to the abuse of antibiotics. Determining how to resensitize MDR bacteria to conventional inefficient antibiotics is of extreme urgency. Here, a low‐temperature photothermal treatment (PTT, 45 °C) is utilized with red phosphorus nanoparticl...

In the present work, the biomedical as-cast pure Mg, Mg–1Ca and Mg–2Sr alloys were processed with equal channel angular pressing (ECAP) technique to develop ultrafine microstructure within the materials, and their microstructures, mechanical properties, degradation behavior, cytocompatibility in vitro and biocompatibility in vivo were studied compr...

Bacterial infection and related diseases are threatening the health of human beings. Photocatalytic disinfection as a simple and low-cost disinfection strategy is attracting more and more attention. In this work, TiO2 nanoparticles (NPs) were modified by co-doping of Ce and Er using the sol-gel method, which endowed TiO2 NPs with enhanced visible l...

Study designBiomechanical analysis of scoliosis instrumentation using superelastic Nickel–titanium shape memory (SNT) rods. Objective To compare SNT with conventional Titanium (Ti) and Cobalt–chrome (Co–Cr) rods. Summary of background dataA clinical trial has documented comparable efficacy between two adolescent idiopathic scoliosis (AIS) cohorts i...

A variety of bioinorganic ions have been reported to alter different cellular functions, including the transport of potassium (K⁺) and calcium (Ca²⁺) ions, while also modulating signal transduction, energy metabolism and cell proliferation due to the electro-potential change of the cell membrane. It was recently reported that the presence of such b...

Bacterial infection is seriously threatening human health all over the world, especially with the emergence of increasing drug-fast bacteria. It is urgent to develop a drug-free strategy to kill bacteria rapidly and efficiently. In this work, humic acid (HuA) encapsulated zeolitic imidazole framework-8 (ZIF-8) (HuA@ZIF-8) nanocomposites are synthes...

Using noninvasive stimulation of cells to control cell fate and improve bone regeneration by optical stimulation can achieve the aim of precisely orchestrating biological activities. In this study, we create a fast and repeatable photoelectric responsive microenvironment around an implant using a bismuth sulfide/hydroxyapatite (BS/HAp) film. The un...

Growing evidence suggests that the physical microenvironment can guide cell fate. However, cells sense cues from the adjacent physical microenvironment over a limited distance. In the present study, murine mesenchymal stem cells (MSCs) and murine preosteoblastic cells (MC3T3-E1) behaviors are regulated by the cell–material interface using ordered-m...

Xerogels usually possess stable structure and have a low swelling rate due to their inferior dynamics. Herein, a xerogel were synthesized by "imitative" click chemistry based on lipoic acid for picking up bacteria on wound sites and thus accelerating tissue repair. The cross-linking structure of disulfide and thioether inside the xerogel not only e...

The application of photothermal therapy to treat bacterial infections remains a challenge, as the high temperatures required for bacterial elimination can damage healthy tissues. Here, we develop an exogenous antibacterial agent consisting of zinc-doped Prussian blue (ZnPB) that kills methicillin-resistant Staphylococcus aureus in vitro and in a ra...