Synthetic hydroxyapatite: a recruiting platform for biologically active molecules

Bone Morphogenetic Protein 7-Loaded Gelatin Methacrylate/Oxidized Sodium Alginate/Nano-Hydroxyapatite Composite Hydrogel for Bone Tissue Engineering

Background

Bone tissue engineering (BTE) is a promising alternative to autologous bone grafting for the clinical treatment of bone defects, and inorganic/organic composite hydrogels as BTE scaffolds are a hot spot in current research. The construction of nano-hydroxyapatite/gelatin methacrylate/oxidized sodium alginate (nHAP/GelMA/OSA), abbreviated as HGO, composite hydrogels loaded with bone morphogenetic protein 7 (BMP7) will provide a suitable 3D microenvironment to promote cell aggregation, proliferation, and differentiation, thus facilitating bone repair and regeneration.

Methods

Dually-crosslinked hydrogels were fabricated by combining GelMA and OSA, while HGO hydrogels were formulated by incorporating varying amounts of nHAP. The hydrogels were physically and chemically characterized followed by the assessment of their biocompatibility. BMP7-HGO (BHGO) hydrogels were fabricated by incorporating suitable concentrations of BMP7 into HGO hydrogels. The osteogenic potential of BHGO hydrogels was then validated through in vitro experiments and using rat femoral defect models.

Results

The addition of nHAP significantly improved the physical properties of the hydrogel, and the composite hydrogel with 10% nHAP demonstrated the best overall performance among all groups. The selected concentration of HGO hydrogel served as a carrier for BMP7 loading and was evaluated for its osteogenic potential both in vivo and in vitro. The BHGO hydrogel demonstrated superior in vitro osteogenic induction and in vivo potential for repairing bone tissue compared to the outcomes observed in the blank control, BMP7, and HGO groups.

Conclusion

Using hydrogel containing 10% HGO appears promising for bone tissue engineering scaffolds, especially when loaded with BMP7 to boost its osteogenic potential. However, further investigation is needed to optimize the GelMA, OSA, and nHAP ratios, along with the BMP7 concentration, to maximize the osteogenic potential.

In-depth knowledge of the low-temperature hydrothermal synthesis of nanocrystalline hydroxyapatite from waste green mussel shell (Perna Viridis)

ABSTRACTThis study presents the use of a low-temperature hydrothermal method for extracting calcium sources from green mussel shell (P. Viridis) wastes and converting them into synthetic nanosized hydroxyapatite (HA). In this study, raw mussel shells were washed, pulverised, and sieved to start producing a fine calcium carbonate-rich powder. XRD quantitative analysis confirmed that the powder contains 97.6 wt. % aragonite. This powder was then calcined for 5 h at 900 °C to remove water, salt, and mud, yielding a calcium-rich feedstock with major minerals of calcite (68.7 wt.%), portlandite (24.7 wt.%), and minor aragonite (6.5 wt.%). The calcined powders were dissolved in aqueous stock solutions of HNO3 and NH4OH before hydrothermally reacting with phosphoric acid [(NH4)2HPO4], yielding pure, nanoscale (16-18 nm) carbonated HA crystals, according to XRD, FT-IR, and SEM analyses. The use of a low-temperature hydrothermal method for a feedstock powder produced by the calcination of low-cost mussel shell wastes would be a valuable processing approach for the industry's development of large-scale hydroxyapatite nanoparticle production.

Systemically administered zoledronic acid activates locally implanted synthetic hydroxyapatite particles enhancing peri-implant bone formation: A regenerative medicine approach to improve fracture fixation

Fracture fixation in an ageing population is challenging and fixation failure increases mortality and societal costs. We report a novel fracture fixation treatment by applying a hydroxyapatite (HA) based biomaterial at the bone-implant interface and biologically activating the biomaterial by systemic administration of a bisphosphonate (zoledronic acid, ZA). We first used an animal model of implant integration and applied a calcium sulphate (CaS)/HA biomaterial around a metallic screw in the tibia of osteoporotic rats. Using systemic ZA administration at 2-weeks post-surgery, we demonstrated that the implant surrounded by HA particles showed significantly higher peri‑implant bone formation compared to the unaugmented implants at 6-weeks. We then evaluated the optimal timing (day 1, 3, 7 and 14) of ZA administration to achieve a robust effect on peri‑implant bone formation. Using fluorescent ZA, we demonstrated that the uptake of ZA in the CaS/HA material was the highest at 3- and 7-days post-implantation and the uptake kinetics had a profound effect on the eventual peri‑implant bone formation. We furthered our concept in a feasibility study on trochanteric fracture patients randomized to either CaS/HA augmentation or no augmentation followed by systemic ZA treatment. Radiographically, the CaS/HA group showed signs of increased peri‑implant bone formation compared with the controls. Finally, apart from HA, we demonstrated that the concept of biologically activating a ceramic material by ZA could also be applied to β-tricalcium phosphate. This novel approach for fracture treatment that enhances immediate and long-term fracture fixation in osteoporotic bone could potentially reduce reoperations, morbidity and mortality. STATEMENT OF SIGNIFICANCE: • Fracture fixation in an ageing population is challenging. Biomaterial-based augmentation of fracture fixation devices has been attempted but lack of satisfactory biological response limits their widespread use. • We report the biological activation of locally implanted microparticulate hydroxyapatite (HA) particles placed around an implant by systemic administration of the bisphosphonate zoledronic acid (ZA). The biological activation of HA by ZA enhances peri‑implant bone formation. •Timing of ZA administration after HA implantation is critical for optimal ZA uptake and consequently determines the extent of peri‑implant bone formation. • We translate the developed concept from small animal models of implant integration to a proof-of-concept clinical study on osteoporotic trochanteric fracture patients. • ZA based biological activation can also be applied to other calcium phosphate biomaterials.

Enhanced Adsorption Stability and Biofunction Durability with Phosphonate-Grafted, PEGylated Copolymer on Hydroxyapatite Surface

Nonfouling surfaces are crucial in applications such as biosensors, medical implants, marine coatings, and drug delivery vehicles. However, their long-term coating stability and robust surface binding strength in physiological media remain challenging. Herein, a phosphonate-grafted, PEGylated copolymer on the hydroxyapatite (HA) surface is proposed to significantly improve the adsorption stability and thus enhance the biofunction durability accordingly. The phosphoryl (-PO3) grafted branch is employed in the functional polymer to facilitate attaching to the HA substrate. In addition, the polymer integrates the nonfouling polymer brushes of poly(ethylene glycol) (PEG) with the cell-adhesive moiety of cyclic Arg-Gly-Asp-d-Phe-Cys peptides (cRGD). A systematic study on the as-synthesized PEGylated graft copolymer indicates a synergistic binding mechanism of the NH2 and PO3 groups to HA, achieving a high surface coverage with desirable adsorption stability. The cRGD/PEGylated copolymers of optimized grafting architecture are proven to effectively adsorb to HA surfaces as a self-assembled copolymer monolayer, showing stability with minimal desorption even in a complex, physiological medium and effectively preventing nonspecific protein adsorption as examined with X-ray photoelectron spectroscopy (XPS) and a quartz crystal microbalance with dissipation (QCM-D). Direct adhesion assays further confirm that the enhanced coating stability and biofunction durability of the phosphonate-grafted, cRGD-PEGylated copolymer can considerably promote osteoblast attachment on HA surfaces, meanwhile preventing microbial adhesion. This research has resulted in a solution of self-assembly polymer structure optimization that exhibits stable nonfouling characteristics.

Hydroxyapatite: An antibiotic recruiting moiety for local treatment and prevention of bone infections

Treatment of chronic osteomyelitis by radical debridement and filling of the dead space with antibiotic containing calcium sulfate/hydroxyapatite (CaS/HA) bone substitute has shown excellent long-term outcomes. However, in extensive infections, sessile bacteria may remain in bone cells or soft tissues protected by biofilm leading to recurrences. The primary aim of this study was to evaluate if systemically administrated tetracycline (TET) could bind to pre-implanted HA particles and impart an antibacterial effect locally. In vitro studies indicated that the binding of TET to nano- and micro-sized HA particles was rapid and plateaued already at 1 h. Since protein passivation of HA after in-vivo implantation could affect HA-TET interaction, we investigated the effect of serum exposure on HA-TET binding in an antibacterial assay. Although, serum exposure reduced the zone of inhibition (ZOI) of Staphylococcus aureus, a significant ZOI could still be observed after pre-incubation of HA with serum. We could in addition show that zoledronic acid (ZA) competes for the same binding sites as TET and that exposure to high doses of ZA led to reduced TET-HA binding. In an in-vivo setting, we then confirmed that systemically administered TET seeks HA particles that were pre-implanted in muscle and subcutaneous pouches in rats and mice respectively, preventing HA particles from being colonized by S. aureus. Clinical Significance: This study describes a new drug delivery method that could prevent bacterial colonization of a HA biomaterial and reduce recurrences in bone infection.

Osteogenic and anti-inflammatory effect of the multifunctional bionic hydrogel scaffold loaded with aspirin and nano-hydroxyapatite

Although tissue engineering offered new approaches to repair bone defects, it remains a great challenge to create a bone-friendly microenvironment and rebuild bone tissue rapidly by a scaffold with a bionic structure. In this study, a multifunctional structurally optimized hydrogel scaffold was designed by integrating polyvinyl alcohol (PVA), gelatin (Gel), and sodium alginate (SA) with aspirin (ASA) and nano-hydroxyapatite (nHAP). The fabrication procedure is through a dual-crosslinking process. The chemical constitution, crystal structure, microstructure, porosity, mechanical strength, swelling and degradation property, and drug-release behavior of the hydrogel scaffold were analyzed. Multi-hydrogen bonds, electrostatic interactions, and strong "egg-shell" structure contributed to the multi-network microstructure, bone tissue-matched properties, and desirable drug-release function of the hydrogel scaffold. The excellent performance in improving cell viability, promoting cell osteogenic differentiation, and regulating the inflammatory microenvironment of the prepared hydrogel scaffold was verified using mouse pre-osteoblasts (MC3T3-E1) cells. And the synergistic osteogenic and anti-inflammatory functions of aspirin and nano-hydroxyapatite were also verified. This study provided valuable insights into the design, fabrication, and biological potential of multifunctional bone tissue engineering materials with the premise of constructing a bone-friendly microenvironment.

Systemic rifampicin shows accretion to locally implanted hydroxyapatite particles in a rat abdominal muscle pouch model

Introduction: biomaterials combined with antibiotics are routinely used for the management of bone infections. After eluting high concentrations of antibiotics during the first week, sub-inhibitory concentrations of antibiotics may lead to late repopulation of recalcitrant bacteria. Recent studies have shown that systemically given antibiotics like tetracycline and rifampicin (RIF) could seek and bind to locally implanted hydroxyapatite (HA). The aim of this in vivo study was to test if systemically administered rifampicin could replenish HA-based biomaterials with or without prior antibiotic loading to protect the material from late bacterial repopulation. Methods: in vivo accretion of systemically administered RIF to three different types of HA-based materials was tested. In group 1, nano (n)- and micro (m)-sized HA particles were used, while group 2 consisted of a calcium sulfate / hydroxyapatite (CaS / HA) biomaterial without preloaded antibiotics gentamycin (GEN) or vancomycin (VAN), and in group 3, the CaS / HA material contained GEN (CaS / HA + GEN) or VAN (CaS / HA + VAN). The above materials were implanted in an abdominal muscle pouch model in rats, and at 7 d post-surgery, the animals were assigned to a control group (i.e., no systemic antibiotic) and a test group (i.e., animals receiving one single intraperitoneal injection of RIF each day (4 mg per rat) for 3 consecutive days). Twenty-four hours after the third injection, the animals were sacrificed and the implanted pellets were retrieved and tested against Staphylococcus aureus ATCC 25923 in an agar diffusion assay. After overnight incubation, the zone of inhibition (ZOI) around the pellets were measured. Results: in the control group, 2 / 6 CaS / HA + GEN pellets had a ZOI, while all other harvested pellets had no ZOI. No pellets from animals in test group 1 had a ZOI. In test group 2, 10 / 10 CaS / HA pellets showed a ZOI. In test group 3, 5 / 6 CaS / HA + GEN and 4 / 6 CaS / HA + VAN pellets showed a ZOI. Conclusions: in this proof-of-concept study, we have shown that a locally implanted biphasic CaS / HA carrier after 1 week can be loaded by systemic RIF administration and exert an antibacterial effect. Further in vivo infection models are necessary to validate our findings.

Longitudinal in vivo biodistribution of nano and micro sized hydroxyapatite particles implanted in a bone defect

Hydroxyapatite (HA) has been widely used as a bone substitute and more recently as a carrier for local delivery of bone targeted drugs. Majority of the approved HA based biomaterials and drug carriers comprise of micrometer sized particulate HA (mHA) or granules and can therefore only be used for extracellular drug release. This shortcoming could be overcome with the use of cell penetrating HA nanoparticles (nHA) but a major concern with the clinical use of nHA is the lack of data on its in vivo biodistribution after implantation. In this study, we aimed to study the in vivo biodistribution of locally implanted nHA in a clinically relevant tibial void in rats and compare it with mHA or a combination of mHA and nHA. To enable in vivo tracking, HA particles were first labelled with ¹⁴C-zoledronic acid (¹⁴C-ZA), known to have a high binding affinity to HA. The labelled particles were then implanted in the animals and the radioactivity in the proximal tibia and vital organs was detected at various time points (Day 1, 7 and 28) post-implantation using scintillation counting. The local distribution of the particles in the bone was studied with micro-CT. We found that majority (>99.9%) of the implanted HA particles, irrespective of the size, stayed locally at the implantation site even after 28 days and the findings were confirmed using micro-CT. Less than 0.1% radioactivity was observed in the kidney and the spleen at later time points of day 7 and 28. No pathological changes in any of the vital organs could be observed histologically. This is the first longitudinal in vivo HA biodistribution study showing that the local implantation of nHA particles in bone is safe and that nHA could potentially be used for localized drug delivery.

Comparative effectiveness research on proximal femoral nail versus dynamic hip screw in patients with trochanteric fractures: a systematic review and meta-analysis of randomized trials

Background

The treatments for trochanteric fractures try to regain early mobility and limit morbidity and risk of reoperations. The most currently used dynamic hip screw (DHS) and the proximal femoral nail (PFN) are both with pros and cons. We aimed to assess the comparative effectiveness of these interventions for trochanteric fractures by evaluating the surgical performance and postoperative outcomes.

Methods

PubMed, Web of Science and Cochrane Central Register were searched for RCTs comparing DHS and PFN for trochanteric fractures. All selected studies and the risk of bias were assessed. Clinical data including operative time, intraoperative blood loss, intraoperative fluoroscopy time, successful closed reduction and complications like nonunion, implant failure and reoperation were recorded. Random-effects models were used in Review Manager software, and GRADE was applied for the interpretation of the evidence.

Results

From 286 identified trials, twelve RCTs including 1889 patients were eligible for inclusion; six RCTs directly comparing DHS with PFN, while other six compared DHS with proximal femoral nail antirotation (PFNA). Compared to DHS, PFN had shorter operative time and led to less intraoperative blood loss. However, DHS need less intraoperative fluoroscopy time than PFN. No difference was seen for the achievement of closed reduction. For risk of postoperative complications, no difference was seen between PFN and DHS for non-union, risk of implant failure and revision surgery.

Conclusions

PFN(A) resulted in a shorter operative time and less intraoperative blood loss compared to DHS. However, no difference was seen for postoperative complications.

Trial registration PROSPERO: CRD42021239974.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03189-z.

A New Augmentation Method for Improved Screw Fixation in Fragile Bone

Pertrochanteric fractures (TF) due to osteoporosis constitute nearly half of all proximal femur fractures. TFs are treated with a surgical approach and fracture fixation is achieved using metallic fixation devices. Poor quality cancellous bone in osteoporotic patients makes anchorage of a fixation device challenging, which can lead to failure of the fracture fixation. Methods to reinforce the bone-implant interface using bone cement (PMMA) and other calcium phosphate cements in TFs have been described earlier but a clear evidence on the advantage of using such biomaterials for augmentation is weak. Furthermore, there is no standardized technique for delivering these biomaterials at the bone-implant interface. In this study, we firstly describe a method to deliver a calcium sulphate/hydroxyapatite (CaS/HA) based biomaterial for the augmentation of a lag-screw commonly used for TF fixation. We then used an osteoporotic Sawbones model to study the consequence of CaS/HA augmentation on the immediate mechanical anchorage of the lag-screw to osteoporotic bone. Finally, as a proof-of-concept, the method of delivering the CaS/HA biomaterial at the bone-implant interface as well as spreading of the CaS/HA material at this interface was tested in patients undergoing treatment for TF as well as in donated femoral heads. The mechanical testing results indicated that the CaS/HA based biomaterial increased the peak extraction force of the lag-screw by 4 times compared with un-augmented lag-screws and the results were at par with PMMA. The X-ray images from the patient series showed that it was possible to inject the CaS/HA material at the bone-implant interface without applying additional pressure and the CaS/HA material spreading was observed at the interface of the lag-screw threads and the bone. Finally, the spreading of the CaS/HA material was also verified on donated femoral heads and micro-CT imaging indicated that the entire length of the lag-screw threads was covered with the CaS/HA biomaterial. In conclusion, we present a novel method for augmenting a lag-screw in TFs, which could potentially reduce the risk of fracture fixation failure and reoperation in fragile osteoporotic patients.

Bone mineral: A trojan horse for bone cancers efficient mitochondria targeted delivery and tumor eradication with nano hydroxyapatite containing doxorubicin

Efficient systemic pharmacological treatment of solid tumors is hampered by inadequate tumor concentration of cytostatics necessitating development of smart local drug delivery systems. To overcome this, we demonstrate that doxorubicin (DOX), a cornerstone drug used for osteosarcoma treatment, shows reversible accretion to hydroxyapatite (HA) of both nano (nHA) and micro (mHA) size. nHA particles functionalized with DOX get engulfed in the lysosome of osteosarcoma cells where the acidic microenvironment causes a disruption of the binding between DOX and HA. The released DOX then accumulates in the mitochondria causing cell starvation, reduced migration and apoptosis. The HA+DOX delivery system was also tested in-vivo on osteosarcoma bearing mice. Locally delivered DOX via the HA particles had a stronger tumor eradication effect compared to the controls as seen by PET-CT and immunohistochemical staining of proliferation and apoptosis markers. These results indicate that in addition to systemic chemotherapy, an adjuvant nHA could be used as a carrier for intracellular delivery of DOX for prevention of tumor recurrence after surgical resection in an osteosarcoma. Furthermore, we demonstrate that nHA particles are pivotal in this approach but a combination of nHA with mHA could increase the safety associated with particulate nanomaterials while maintaining similar therapeutic potential.

Sustained and controlled delivery of doxorubicin from an in-situ setting biphasic hydroxyapatite carrier for local treatment of a highly proliferative human osteosarcoma

Doxorubicin (DOX) is a cornerstone drug in the treatment of osteosarcoma. However, achieving sufficient concentration in the tumor tissue after systemic administration with few side effects has been a challenge. Even with the most advanced nanotechnology approaches, less than 5% of the total administered drug gets delivered to the target site. Alternatives to increase the local concentration of DOX within the tumor using improved drug delivery methods are needed. In this study, we evaluate a clinically approved calcium sulfate/hydroxyapatite (CaS/HA) carrier, both in-vitro and in-vivo, for local, sustained and controlled delivery of DOX to improve osteosarcoma treatment. In-vitro drug release studies indicated that nearly 28% and 36% of the loaded drug was released over a period of 4-weeks at physiological pH (7.4) and acidic pH (5), respectively. About 63% of the drug had been released after 4-weeks in-vivo. The efficacy of the released drug from the CaS/HA material was verified on two human osteosarcoma cell lines MG-63 and 143B. It was demonstrated that the released drug fractions functioned the same way as the free drug without impacting its efficacy. Finally, the carrier system with DOX was assessed using two clinically relevant human osteosarcoma xenograft models. Compared to no treatment or the clinical standard of care with systemic DOX administration, the delivery of DOX using a CaS/HA biomaterial could significantly hinder tumor progression by inhibiting angiogenesis and cell proliferation. Our results indicate that a clinically approved CaS/HA biomaterial containing cytostatics could potentially be used for the local treatment of osteosarcoma. STATEMENT OF SIGNIFICANCE: The triad of doxorubicin (DOX), methotrexate and cisplatin has routinely been used for the treatment of osteosarcoma. These drugs dramatically improved the prognosis, but 45-55% of the patients respond poorly to the treatment with low 5-year survival. In the present study, we repurpose the cornerstone drug DOX by embedding it in a calcium sulfate/hydroxyapatite (CaS/HA) biomaterial, ensuring a spatio-temporal drug release and a hypothetically higher and longer lasting intra-tumoral concentration of DOX. This delivery system could dramatically hinder the progression of a highly aggressive osteosarcoma compared to systemic administration, by inhibiting angiogenesis and cell proliferation. Our data show an efficient method for supplementary osteosarcoma treatment with possible rapid translational potential due to clinically approved constituents.

Augmenting a dynamic hip screw with a calcium sulfate/hydroxyapatite biomaterial

Internal fixation failure in hip fractures can lead to reoperation. Calcium sulfate/hydroxyapatite (CaS/HA) is a biomaterial that can be used for augmenting fracture fixation. We aimed to determine whether an injection of 2 ml CaS/HA increases the fixation of a dynamic hip screw inserted in synthetic and human trabecular bone. The study consists of two parts: 1) synthetic bone blocks (n = 74), with three subgroups: empty (cannulated screw, no injection), cannulated, and fenestrated; and 2) osteoporotic human femoral heads (n = 29), with the same subgroups. The heads were imaged using µCT. Bone volume fraction, insertion angle, and head diameter were measured. Pullout tests were performed and peak force, stiffness, and work were measured. The fenestrated group showed increases in pullout strength compared to no injection in the synthetic blocks. The cannulated group showed a higher pullout strength in low-density blocks. In the femoral heads, the variation was larger and there were no significant differences between groups. The bone volume fraction correlated with the peak force and work, and the insertion angle correlated with the stiffness. CaS/HA can improve the fixation of a dynamic hip screw. For clinical use, spreading of the material around the threads of the screw must be ensured.

Long-Term Response to a Bioactive Biphasic Biomaterial in the Femoral Neck of Osteoporotic Rats

Osteoporosis often leads to fragility fractures of the hip, resulting in impaired quality of life and increased mortality. Augmenting the proximal femur could be an attractive option for prevention of fracture or fixation device failure. We describe a tissue engineering based strategy to enhance long-term bone formation in the femoral neck of osteoporotic rats by locally delivering bioactive molecules; recombinant human bone morphogenic protein-2 (rhBMP-2), and zoledronic acid (ZA) by using a calcium sulfate/hydroxyapatite (CaS/HA) biomaterial. A defect was created by reaming the femoral neck canal of osteoporotic (OVX) rats and they were treated as follows: G1. Empty, G2. CaS/HA, G3. CaS/HA+Systemic ZA, G4. CaS/HA+Local ZA, and G5. CaS/HA+Local ZA+rhBMP-2. Bone formation was evaluated 6 months after treatment. Further, radioactively labeled 14C-ZA was used to study the bioavailability of ZA at the defect location, which was determined by using scintillation counting. Micro-CT indicated significantly higher bone volume in groups G4 and G5 compared with the other treatment groups. This was confirmed qualitatively by histological assessment. Addition of rhBMP-2 gave no additional benefit in this model. Local delivery of ZA performed better than systemic administration of ZA. Mechanical testing showed no differences between the groups, likely reflecting that the addition of bioactive molecules had limited effect on cortical bone or the choice of mechanical testing setup was not optimal. Scintillation counting revealed higher amounts of 14C-ZA present in the treated leg of G4 compared with its contralateral control and compared with G3, indicating that local ZA delivery can be used to achieve high local concentrations without causing a systemic effect. This long-term study shows that local delivery of ZA using a CaS/HA carrier can regenerate cancellous bone in the femoral neck canal and has clear implications for enhancing implant integration and fixation in fragile bone.

Bone mineral as a drug-seeking moiety and a waste dump

Bone is a dynamic tissue with a quarter of the trabecular and a fifth of the cortical bone being replaced continuously each year in a complex process that continues throughout an individual's lifetime. Bone has an important role in homeostasis of minerals with non-stoichiometric hydroxyapatite bone mineral forming the inorganic phase of bone. Due to its crystal structure and chemistry, hydroxyapatite (HA) and related apatites have a remarkable ability to bind molecules. This review article describes the accretion of trace elements in bone mineral giving a historical perspective. Implanted HA particles of synthetic origin have proved to be an efficient recruiting moiety for systemically circulating drugs which can locally biomodulate the material and lead to a therapeutic effect. Bone mineral and apatite however also act as a waste dump for trace elements and drugs, which significantly affects the environment and human health. Cite this article: Bone Joint Res 2020;9(10):709-718.