Manipulation of Morphology, Particle Size of Barium Sulfate and the Interacting Mechanism of Methyl Glycine Diacetic Acid.

In this paper, methyl glycine diacetic acid (MGDA) was found to have great influence on the morphology and particle size of barium sulfate. The effects of additive, concentration, value of pH and reaction temperature on the morphology and particle size of barium sulfate were studied in detail. The results show that the concentration of reactant and temperature have little effect on the particle size of barium sulfate. However, the pH conditions of the solution and the dosage of MGDA can apparently affect the particle size distribution of barium sulfate. The particle size of barium sulfate particles increases and the morphology changes from polyhedral to rice-shaped with the decreasing of the dosage of MGDA. In solution with higher pH, smaller and rice-shaped barium sulfate was obtained. To investigate the interacting mechanism of MGDA, the binding energy between MGDA and barium sulfate surface was calculated. It was found that the larger absolute value of the binding energy would result in stronger growth inhibition on the crystal face. Finally, the experimental data and theoretical calculations were combined to elucidate the interacting mechanism of the additive on the morphology and particle size of barium sulfate.

Determination of barium sulfate in barite ore by phase conversion-partial pressure-corrected headspace gas chromatography.

Barium sulfate (BaSO4) content is used to evaluate the grade of barite ore. In the present study, we report a method to determine the BaSO4 content in barite ore by phase conversion-headspace gas chromatography with partial pressure correction. In this method, the ore sample is roasted with sodium carbonate and potassium carbonate after pretreatment with hydrochloric acid. The roasted product is subsequently placed in a closed headspace bottle to react with hydrochloric acid. The ratio of CO2 to O2 signals is detected by a thermal conductivity detector for gas chromatography. Finally, the BaSO4 content in barite ore is calculated using this ratio. The method demonstrates good precision (relative standard deviation < 0.84%) and accuracy (relative error < 3.40%), with the uncertainty at 95% confidence interval at approximately +/- 0.57%. Moreover, this approach is expected to be used for the batch testing of BaSO4 content in barite ores in industrial applications.

Alternative radiopacifiers for polymethyl methacrylate bone cements: Silane-treated anatase titanium dioxide and yttria-stabilised zirconium dioxide.

Poly (methyl methacrylate) (PMMA) bone cement is widely used for anchoring joint arthroplasties. In cement brands approved for these procedures, micron-sized particles (usually barium sulphate, BaSO4) act as the radiopacifier. It has been postulated that these particles act as sites for crack initiation and subsequently cement fatigue. This study investigated whether alternative radiopacifiers, anatase titanium dioxide (TiO2) and yttria-stabilised zirconium dioxide (ZrO2), could improve the in vitro mechanical, fatigue crack propagation and biological properties of polymethyl methacrylate (PMMA) bone cement and whether their coating with a silane could further enhance cement performance. Cement samples containing 0, 5, 10, 15, 20 and 25%w/w TiO2 or ZrO2 and 10%w/w silane-treated TiO2 or ZrO2 were prepared and characterised in vitro in terms of radiopacity, compressive and bending strength, bending modulus, fatigue crack propagation, hydroxyapatite forming ability and MC3T3-E1 cell attachment and viability. Cement samples with greater than 10%w/w TiO2 and ZrO2 had a similar radiopacity to the control 10%w/w BaSO4 cement and commercial products. The addition of TiO2 and ZrO2 to bone cement reduced the bending strength and fracture toughness and increased fatigue crack propagation due to the formation of agglomerations and voids. Silane treating TiO2 reversed this effect, enhancing the dispersion and adhesion of particles to the PMMA matrix and resulted in improved mechanical properties and fatigue crack propagation resistance. Silane-treated TiO2 cements had increased nucleation of hydroxyapatite and MC3T3-E1 cell attachment in vitro, without significantly compromising cell viability. This research has demonstrated that 10%w/w silane-treated anatase TiO2 is a promising alternative radiopacifier for PMMA bone cement offering additional benefits over conventional BaSO4 radiopacifiers.

Shielding effect of radiation dose reduction fiber during the use of C-arm fluoroscopy: a phantom study.

This study evaluated the shielding effect of a newly developed dose-reduction fiber (DRF) made from barium sulfate, in terms of radiation doses delivered to patients' radiosensitive organs and operator during C-arm fluoroscopy and its impact on the quality of images. A C-arm fluoroscopy unit was placed beside a whole-body phantom. Radiophotoluminescent glass dosimeters were attached to the back and front of the whole-body phantom at 20 cm intervals. Radiation doses were measured without DRF and with it applied to the back (position 1), front (position 2) or both sides (position 3) of the phantom. To investigate the impact of DRF on the quality of fluoroscopic images, step-wedge and modulation transfer function phantoms were used. The absorbed radiation doses to the back of the phantom significantly decreased by 25.3-88.8% after applying DRF to positions 1 and 3. The absorbed radiation doses to the front of the phantom significantly decreased by 55.3-93.6% after applying DRF to positions 2 and 3. The contrast resolution values for each adjacent step area fell in the range 0.0119-0.0209, 0.0128-0.0271, 0.0135-0.0339 and 0.0152-0.0339 without and with DRF applied to positions 1, 2 and 3, respectively. The investigated DRF effectively reduces absorbed radiation doses to patients and operators without decreasing the quality of C-arm fluoroscopic images. Therefore, routine clinical use of the DRF is recommended during the use of C-arm fluoroscopy.

Benefits of Polydopamine as Particle/Matrix Interface in Polylactide/PD-BaSO4 Scaffolds.

This work reports the versatility of polydopamine (PD) when applied as a particle coating in a composite of polylactide (PLA). Polydopamine was observed to increase the particle-matrix interface strength and facilitate the adsorption of drugs to the material surface. Here, barium sulfate radiopaque particles were functionalized with polydopamine and integrated into a polylactide matrix, leading to the formulation of a biodegradable and X-ray opaque material with enhanced mechanical properties. Polydopamine functionalized barium sulfate particles also facilitated the adsorption and release of the antibiotic levofloxacin. Analysis of the antibacterial capacity of these composites and the metabolic activity and proliferation of human dermal fibroblasts in vitro demonstrated that these materials are non-cytotoxic and can be 3D printed to formulate complex biocompatible materials for bone fixation devices.

Sub-10 nm Radiolabeled Barium Sulfate Nanoparticles as Carriers for Theranostic Applications and Targeted Alpha Therapy.

Invited for this month's cover is the group of Kristof Zarschler at the University of Dresden, Germany. Read the full text of their Full Paper at 10.1002/open.202000126.

Sub-10†nm Radiolabeled Barium Sulfate Nanoparticles as Carriers for Theranostic Applications and Targeted Alpha Therapy.

The treatment of cancer patients with α-particle-emitting therapeutics continues to gain in importance and relevance. The range of radiopharmaceutically relevant α-emitters is limited to a few radionuclides, as stable chelators or carrier systems for safe transport of the radioactive cargo are often lacking. Encapsulation of α-emitters into solid inorganic systems can help to diversify the portfolio of candidate radionuclides, provided, that these nanomaterials effectively retain both the parent and the recoil daughters. We therefore focus on designing stable and defined nanocarrier-based systems for various clinically relevant radionuclides, including the promising α-emitting radionuclide 224Ra. Hence, sub-10 nm barium sulfate nanocontainers were prepared and different radiometals like 89Zr, 111In, 131Ba, 177Lu or 224Ra were incorporated. Our system shows stabilities of >90 % regarding the radiometal release from the BaSO4 matrix. Furthermore, we confirm the presence of surface-exposed amine functionalities as well as the formation of a biomolecular corona.

Assessing the geochemical and environmental baseline of heavy metals in soils around hydrothermal hematite-barite-galena veins in Baghin area, Kerman, Iran.

To assess the geochemical and environmental baseline as well as the availability of the heavy elements in soils around the hematite-barite-galena veins in the Baghin area, a total of 70 soil samples were collected and analyzed by ICP-OES for 43 heavy metals and metalloids. Compared to the global soil level or crustal abundance, the calcareous soils are 2-26 magnitudes enriched in Ca, Cu, Pb, Zn, Cd, Se, As, Sb and Sr. The ferruginous soils are highly enriched in Fe, Mo, Pb, Zn, Cd, As, Sb, Ba and Sr, almost 2-49 orders higher than the crustal abundance and global soil level. Additionally, the baritic soils are 3-94 times higher than the crustal and global soil values for Ba, Cu, Mo, Pb, Zn, Ni, Co, Cd, Se, As, Sb and Sr. However, the soils developed on the shale layers are moderately enriched in As, Zn, Se, Sb, Ba, Pb and Sr. The high concentrations of heavy metals are possibly related to the presence of minor sulfide minerals in barite-rich soils or adsorption by Fe-oxy-hydroxides formed by oxidation of sulfide minerals. Therefore, the oxidation of minor sulfide minerals in barite veins may be prone to acid mine generation and of environmental concern. The inhalation of silica dusts released by silica-rich barite ores (20% SiO2) during crushing, milling, as well as using in drilling mud may trigger silicosis. Despite the high baseline values of some heavy metals and metalloids, the presence of Fe-oxy-hydroxides and clay minerals in the soils could play significant roles in sequestering the toxic effects of heavy metals contamination in soil, groundwater, plants, wildlife and humans.

Perovskite nanocrystals fluorescence nanosensor for ultrasensitive detection of trace melamine in dairy products by the manipulation of inner filter effect of gold nanoparticles.

Barium sulfate-coated CsPbBr3 perovskite nanocrystals (CsPbBr3 NCs@BaSO4) was successfully synthesized that exhibited stable and intense fluorescence property in aqueous buffer. With the CsPbBr3 NCs@BaSO4 as signal readout, an ultrasensitive fluorescence nanosensor was developed for turn-on determination of melamine by the manipulation of inner filter effect of citrate-protected gold nanoparticles (AuNPs). The fluorescence of the CsPbBr3 NCs@BaSO4 was remarkably quenched by the AuNPs due to inner filter effect. This inner filter effect could be weakened by the addition of melamine as a result of melamine-triggering aggregation of the AuNPs and subsequently led to a recovery in the fluorescence of the CsPbBr3 NCs@BaSO4. The recovery ratio was proportional to the concentration of melamine in the range of 5.0-500.0 nmol/L. The limit of detection was 0.42 nmol/L and the relative standard deviation was 4.0% for the repetitive determination of 500.0 nmol/L melamine solution (n = 11). The nanosensor was successfully applied to analysis of melamine in dairy product samples.

Light Weight, Easy Formable and Non-ToxicPolymer-Based Composites for Hard X-rayShielding: A Theoretical and Experimental Study.

Composite lightweight materials for X-ray shielding applications were studied anddeveloped with the goal of replacing traditional screens made of lead and steel, with innovativematerials with similar shielding properties, but lighter, more easily formed and workable, with lowerimpact on the environment and reduced toxicity for human health. New epoxy-based compositesadditivated with barium sulfate and bismuth oxide were designed through simulations performedwith software based on Geant4. Then, they were prepared and characterized using differenttechniques starting from digital radiography in order to test the radiopacity of the composites,in comparison with traditional materials. The lower environmental impact and toxicity of theseinnovative screens were quantified by Life Cycle Assessment (LCA) calculation based on the ecoinventdatabase, within the openLCA framework. Optimized mixtures are (i) 20% epoxy/60% bismuthoxide/20% barite, which guarantees the best performance in X-ray shielding, largely overcomingsteel, but higher in costs and a weight reduction of circa 60%; (ii) 20% epoxy/40% bismuth oxide/40%barite which has slightly lower performances in shielding, but it is lighter and cheaper than thefirst one and (iii) the 20% epoxy/20% bismuth oxide/60% barite which is the cheapest material, stillmaintaining the X-ray shielding of steel. Depending on the cost/efficiency request of the specificapplication (industrial ra.

Barium- and Bismuth-loaded Clinoptilolite Micro- and Nano-Particles as Proposed New Efficient Contrast Agents.

AIMS AND OBJECTIVE: Clinoptilolite is one of the natural zeolites. Clinoptilolite particles have a high surface area, negative surface charge, cation adsorption and exchange capacities. Barium sulfate (BaSO4) and bismuth subnitrate (Bi5H9N4O22) suspensions have been used for upper and lower gastrointestinal imaging but Ba2+ and Bi3+ ions are toxic. In the present study, the feasibility of the application of Ba2+- and Bi3+-loaded clinoptilolite micro- and nano-particles in medical imaging was investigated. MATERIALS AND METHODS: Nanoparticles and microparticles of natural clinoptilolite were loaded with Ba2+ and Bi3+ ions. Radiopacities of loaded particles were measured and compared with those of BaSO4 and Bi5H9N4O22. RESULTS: Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles showed more intense X-ray opacities than BaSO4 and Bi5H9N4O22 with equimolar concentrations. Moreover, Ba2+- and Bi3+-loaded clinoptilolite nanoparticles more intensely absorbed X-ray than respective loaded microparticles. CONCLUSION: The present study proposes Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles as new, safe, efficient, and inexpensive contrast agents.

Predicting dissolution and transformation of inhaled nanoparticles in the lung using abiotic flow cells: The case of barium sulfate.

Barium sulfate (BaSO4) was considered to be poorly-soluble and of low toxicity, but BaSO4 NM-220 showed a surprisingly short retention after intratracheal instillation in rat lungs, and incorporation of Ba within the bones. Here we show that static abiotic dissolution cannot rationalize this result, whereas two dynamic abiotic dissolution systems (one flow-through and one flow-by) indicated 50% dissolution after 5 to 6 days at non-saturating conditions regardless of flow orientation, which is close to the in vivo half-time of 9.6 days. Non-equilibrium conditions were thus essential to simulate in vivo biodissolution. Instead of shrinking from 32 nm to 23 nm (to match the mass loss to ions), TEM scans of particles retrieved from flow-cells showed an increase to 40 nm. Such transformation suggested either material transport through interfacial contact or Ostwald ripening at super-saturating conditions and was also observed in vivo inside macrophages by high-resolution TEM following 12 months inhalation exposure. The abiotic flow cells thus adequately predicted the overall pulmonary biopersistence of the particles that was mediated by non-equilibrium dissolution and recrystallization. The present methodology for dissolution and transformation fills a high priority gap in nanomaterial hazard assessment and is proposed for the implementation of grouping and read-across by dissolution rates.

The effects of barium concentration levels on the pulmonary inflammatory response in a rat model of aspiration.

PURPOSE: Barium sulfate (Ba) suspension is the most widely used contrast agent for upper gastrointestinal and videofluoroscopic swallow studies (VFSS). The effect of Ba concentration on lung injury is uncertain. The aims of this study were to explore the effects of different barium concentrations on the respiratory organs and elucidate the underlying mechanisms of these effects in an established animal model of aspiration. METHODS: Animal model study. Eight-week-old male Sprague-Dawley rats were allocated into three groups (n = 12, each group). Two groups underwent tracheal instillation of low (30% w/v) and high (60% w/v) concentration Ba (low-Ba, high-Ba). A control group was instilled with saline. Half of the animals were euthanized on day 2 and the remaining half were euthanized on day 30. Histological and gene analyses were performed. RESULTS: Both low-Ba and high-Ba aspiration caused inflammatory cell infiltration in the lung at 2 days post aspiration with an increase in the expression of inflammatory cytokines. At 30 days post aspiration, small quantities of barium particles remained in the lung of the low-Ba group without any inflammatory reaction. Chronic inflammation was recognized in the high-Ba group up to 30 days post aspiration. CONCLUSION: A small amount of high concentration Ba (60% w/v) caused sustained inflammation in the rat lung at least 30 days after aspiration. Even with a small amount of low concentration Ba aspiration (30% w/v), Ba particles can remain in the lung over a month, causing sustained late effects.

In vivo evaluation of targeted delivery of biological agents using barium sulfate.

This study was aimed to monitor the transit through the intestine by X-ray imaging using barium sulfate (BS) as tracer. The in vitro features of monolithic tablets were correlated with their in vivo behavior in order to provide a tool for the development of targeted formulations containing macromolecular bioactive agents. The impact of BS on various matrices (neutral, ionic) was studied in simulated fluids using the disintegration time (DT) as main parameter. Dry tablets were characterized by spectroscopic methods (X-ray diffraction and Infra-Red) and scanning electron microscopy (SEM). The selected formulations were followed in a beagle dog model. The in vivo and in vitro DT of tablets formulated with BS were compared. Results: anionic excipients carboxymethylcellulose (CMC) and carboxymethylstarch (CMS) protected the active ingredient from the gastric acidity, ensuring its targeted delivery in the intestine. The SEM analysis, before and after transit in simulated fluids, showed that BS remained in the tablets allowing their good follow-up in vivo. The incorporation of 30% protein in tablets with 40% BS had no impact on their behavior. In conclusion, BS and X-ray imagery could be a good alternative to scintigraphy for development of targeted formulations containing high molecular weight bioactive agents.

A novel radiopaque tissue marker for soft tissue localization and in vivo length and area measurements.

PURPOSE: The purpose of the study was to describe the characteristics and demonstrate proof-of-concept and clinical use of a barium sulfate infused polypropylene radiopaque tissue marker for soft tissue localization and in vivo measurement of lengths and areas. METHODS: Marker mechanical properties were evaluated by tensile tests. Biocompatibility was evaluated following 8-12 weeks' implantation in a pig model. Proof-of-concept of marker application was performed in a human cadaveric shoulder model, and methods for CT imaging and measurement of dimensions were established. Lastly, the method of clinical use of the markers was described in one patient undergoing arthroscopic rotator cuff repair (RCR). RESULTS: The radiopaque markers had a tensile strength of 28 ±4.7 N and were associated with minimal to mild inflammatory tissue reaction similar to polypropylene control. CT-based measurements showed relatively high precisions for lengths (0.66 mm), areas (6.97 mm2), and humeral orientation angles (2.1°) in the cadaveric model, and demonstrated 19 ±3 mm medio-lateral tendon retraction and 227 ±3 mm2 increase in tendon area in the patient during 26 weeks following RCR. No radiographic leaching, calcification or local adverse events were observed. CONCLUSIONS: The radiopaque tissue marker was biocompatible and had adequate strength for handling and affixation to soft tissues using standard suturing techniques. The marker could be used with low-dose, sequential CT imaging to quantitatively measure rotator cuff tendon retractions with clinically acceptable accuracy. We envision the radiopaque tissue marker to be useful for soft tissue localization and in vivo measurement of tissue and organ dimensions following surgery.

Construction of catechol-grafted chitosan alginate/barium sulfate microcapsules for computed tomography real-time imaging and gastroretentive drug delivery.

Background: The gastroretentive drug delivery system is an effective administration route, which can improve the bioavailability of the drug and the therapeutic effect by prolonging the release time of the drug and controlling the release rate in the stomach. Methods: Inspired by the excellent adhesion properties of mussel protein, we prepared novel catechol-grafted chitosan alginate/barium sulfate microcapsules (Cat-CA/BS MCs) with mucoadhesive properties and computed tomography (CT) imaging function for gastric drug delivery. First, barium sulfate nanoclusters used as CT contrast agent were synthesized in situ in the Cat-CA/BS MCs through a one-step electronic spinning method. Next, catechol-grafted chitosan as the mucoadhesive moiety was coated on the surface of Cat-CA/BS MCs by polyelectrolyte molecule self-assembly. Results: The prepared Cat-CA/BS MCs could effectively retained in the stomach for 48 hours and successively released ranitidine hydrochloride, which could be used for the treatment of gastric ulcer. Cat-CA/BS MCs exhibited superior CT contrast imaging properties for real-time tracking in vivo after oral administration. Conclusion: These findings demonstrate that Cat-CA/BS MCs serving as multifunctional oral drug carriers possess huge potential in gastroretentive drug delivery and non-invasive visualization.

X-ray shielding structural and properties design for the porous transparent BaSO4/cellulose nanocomposite membranes.

Since effective shielding of X-rays was required in medical, aviation and nuclear fields, a novel X-ray shielding BaSO4/cellulose nanocomposite membrane (BSCM) material with porous transparent structure has been designed. The effects of carboxylated nano-BaSO4 (BS) addition on the physical and morphological properties of the cellulose membrane (CM) were investigated. Meanwhile, the influence of X-ray shielding capacity was studied by different layers of composite membranes and the shielding mechanism of the X-ray was also discussed. Scanning electron microscopy (SEM) images displayed the aggregations of BS in the cellulose surface. Fourier transform infrared spectroscopy (FTIR) showed that the incorporation of BS into CM caused molecular interactions between CM and BS. Brunauer-Emmett-Teller (BET) indicated that the load of BS contributed little to the specific surface area and pore size. Meanwhile, the water vapor transmission rates (WVTR) also stayed at the same level before and after the binding of BS. The swelling ratios, weight loss ratios and mechanical property were decreased along with the addition of BS. The radiation shielding ability was enhanced. Therefore, this work was regarded as a possible example that the BSCM was designed as X-ray radiation shielding material or sandwich filler material in the implication of radiation shielding glass.

Fate of Barium Sulfate Nanoparticles Deposited in the Lungs of Rats.

We have shown that barium [from BaSO4 nanoparticles (NPs)] was cleared from the lungs faster than other poorly soluble NPs and translocated mostly to bone. We now studied barium biokinetics in rats during Study 1: two-year inhalation exposure to 50 mg/m3 BaSO4 NP aerosols, and Study 2: single intratracheal (IT) instillation of increasing doses of BaSO4 NPs or BaCl2. Study 1 showed that lung barium content measured by inductively coupled plasma mass spectrometry increased during 360 days of BaSO4 NP aerosol exposures. An equilibrium was established from that time until 2 years. Barium concentrations in BaSO4-exposed animals were in the order (lungs > lymph nodes > hard bone > bone marrow > liver). In Study 2, there was an increase in lung barium post-IT instillation of BaSO4 NPs while barium from BaCl2 was mostly cleared by day 28. Transmission electron microscopy showed intact BaSO4 NPs in alveolar macrophages and type II epithelial cells, and in tracheobronchial lymph nodes. Using stimulated Raman scattering microscopy, specific BaSO4 Raman spectra were detected in BaSO4 NP-instilled lungs and not in other organs. Thus, we posit that barium from BaSO4 NPs translocates from the lungs mainly after dissolution. Barium ions are then incorporated mostly into the bone and other organs.

Comparison of Three-Dimensional Micro-CT Angiography of Cervical Spinal Cord between Two Contrast Agents.

Purpose: Barium sulfate and lead oxide are commonly used for angiographic studies, but there is no report on the comparison of two contrast agents in angiography of cervical spinal cord. This study was aimed to compare the microvascular architecture of cervical spinal cord in rats after angiography with the barium sulfate agent to the lead oxide agent. Methods: Twelve adult Sprague-Dawley rats were randomly divided into the barium sulfate group (n=6) and the lead oxide group (n=6). Each rat was perfused under the same protocol using either two contrast agents. The angiography was evaluated with the vascular number at different ranks. The cervical spinal cord samples were scanned using micro-CT with low resolution and high resolution. The microvascular parameters, including ratio of vascular volume to tissue volume (VV/TV), vascular number (V.N), diameter (V.Dm), separation (V.Sp), connectivity density (Conn.D), structure model index (SMI), percentage, and volume of vessels at different diameters were measured. Results: The perfusion was better in the barium sulfate group, with more blood vessel trees of rank II and III visible compared to the lead oxide group. Low-resolution micro-CT analysis showed no difference in microvascular parameters except SMI between the two groups. High-resolution micro-CT analysis results showed that V.N and Conn.D of barium sulfate group were 60% and 290% more than those of the lead oxide group; however, V.Sp was 41% less than the lead oxide group. The percentage of vessels with diameter of 10 µm and 20 µm, and the volume of vessels with diameter of less than 100 µm was higher in the barium sulfate group than in the lead oxide group. The SMI index in the barium sulfate group was higher than that in the lead oxide group at both low resolution and high resolution. Conclusions: Compared with lead oxide, barium sulfate is more suitable for perfusion of cervical spinal cord microvessels, and cheap and nontoxic with high resolution.

Multifunctional Coating to Simultaneously Encapsulate Drug and Prevent Infection of Radiopaque Agent.

Poly(methyl methacrylate) (PMMA) bone cements have been widely used in clinical practices. In order to enhance PMMA's imaging performance to facilitate surgical procedures, a supplementation of radiopaque agent is needed. However, PMMA bone cements are still facing problems of loosening and bacterial infection. In this study, a multifunctional coating to simultaneously encapsulate drug and prevent the infection of radiopaque agent has been developed. Barium sulfate (BaSO4), a common radiopaque agent, is used as a substrate material. We successfully fabricated porous BaSO4 microparticles, then modified with hexakis-(6-iodo-6-deoxy)-alpha-cyclodextrin (I-CD) and silver (Ag) to obtain porous BaSO4@PDA/I-CD/Ag microparticles. The porous nature and presence of PDA coating and I-CD on the surface of microparticles result in efficient loading and release of drugs such as protein. Meanwhile, the radiopacity of BaSO4@PDA/I-CD/Ag microparticles is enhanced by this multifunctional coating containing Ba, I and Ag. PMMA bone cements containing BaSO4@PDA/I-CD/Ag microparticles show 99% antibacterial rate against both Staphylococcus aureus (S. aureus) and Escherichia Coli (E. coli), yet without apparently affecting its biocompatibility. Together, this multifunctional coating possessing enhanced radiopacity, controlled drug delivery capability and exceptional antibacterial performance, may be a new way to modify radiopaque agents for bone cements.