Biomedical Tissue Research Articles

Development of a cost-effective compact diode-laser-based photoacoustic sensing instrument for breast tissue diagnosis.

The photoacoustic (PA) technique, a noninvasive pump-probe technique, has found interesting applications in biomedical tissue diagnosis over the last decade. To take it a step further to clinical applications, the PA technique needs to be designed as an instrument focusing on a compact design, reducing the cost, and quickly providing a quantitative diagnosis. This work presents a design and characterization of a cost-effective, compact PA sensing instrument for biomedical tissue diagnosis. A compact laser diode case design is developed to house several laser diodes for PA excitation, and a pulsed current supply unit is also developed in-house to power the laser diodes to generate a 25ns current pulse at a frequency of 20kHz. After PA experimental data acquisition, the signal's frequency spectra were calculated to characterize the tissue quantitatively and correlated with their mechanobiological properties. The corresponding dominant frequency peak in the PA spectral response (PASR) study was low in the fibrofatty normal breast tissue , compared to the dominant frequency peak of in the fibrocystic disease tissue, which had increased glandular and stromal elements, thereby increased tissue density. The histopathological findings correlated with the PASR results, and the fibrocystic breast disease tissue exhibited a higher dominant frequency peak and energy compared to the normal breast tissue. We experimented with an in vitro PASR study of fibrocystic human breast tissues and successfully differentiated different tissue types using quantitative spectral parameters peak frequency, mean frequency, and spectral energy. This gives the potential to take this technique further for cost-effective and quick clinical applications.

PBF-LB fabrication of microgrooves for induction of osteogenic differentiation of human mesenchymal stem cells

Stem cell differentiation has important implications for biomedical device design and tissue engineering. Recently, inherent material properties, including surface chemistry, stiffness, and topography, have been found to influence stem cell fate. Among these, surface topography is a key regulator of stem cells in contact with materials. The most important aspect of ideal bone tissue engineering is to control the organization of the bone extracellular matrix with fully differentiated osteoblasts. Here, we found that laser powder bed fusion (PBF-LB)-fabricated grooved surface inspired by the microstructure of bone, which induced human mesenchymal stem cell (hMSC) differentiation into the osteogenic lineage without any differentiation supplements. The periodic grooved structure was fabricated by PBF-LB which induced cell elongation facilitated by cytoskeletal tension along the grooves. This resulted in the upregulation of osteogenesis via Runx2 expression. The aligned hMSCs successfully differentiated into osteoblasts and further organized the bone mimetic-oriented extracellular matrix microstructure. Our results indicate that metal additive manufacturing technology has a great advantage in controlling stem cell fate into the osteogenic lineage, and in the construction of bone-mimetic microstructural organization. Our findings on material-induced stem cell differentiation under standard cell culture conditions open new avenues for the development of medical devices that realize the desired tissue regeneration mediated by regulated stem cell functions.

Ratiometric near-infrared fluorescent probe for nitroreductase activity enables 3D imaging of hypoxic cells within intact tumor spheroids.

Fluorescent molecular probes that report nitroreductase activity have promise as imaging tools to elucidate the biology of hypoxic cells and report the past hypoxic history of biomedical tissue. This study describes the synthesis and validation of a "first-in-class" ratiometric, hydrophilic near-infrared fluorescent molecular probe for imaging hypoxia-induced nitroreductase activity in 2D cell culture monolayers and 3D multicellular tumor spheroids. The probe's molecular structure is charge-balanced and the change in ratiometric signal is based on Förster Resonance Energy Transfer (FRET) from a deep-red, pentamethine cyanine donor dye (Cy5, emits ∼660 nm) to a linked near-infrared, heptamethine cyanine acceptor dye (Cy7, emits ∼780 nm). Enzymatic reduction of a 4-nitrobenzyl group on the Cy7 component induces a large increase in Cy7/Cy5 fluorescence ratio. The deep penetration of near-infrared light enables 3D optical sectioning of intact tumor spheroids, and visualization of individual hypoxic cells (i.e., cells with raised Cy7/Cy5 ratio) as a new way to study tumor spheroids. Beyond preclinical imaging, the near-infrared fluorescent molecular probe has high potential for ratiometric imaging of hypoxic tissue in living subjects.

Three-dimensional dynamic homogenous modeling: The biomechanical influences of leg tissue stiffness on pressure performance of compression biomedical therapeutic textiles.

Patient compliance and therapeutic precision of compression textiles (CTs) are frequently limited by the inaccurate pressure distributions along biological bodies in physical-based compression therapy. Therefore, the biomechanical influences of physiological tissue material characteristics of lower extremities on compression generations of CTs need to be explored systematically to improve pressure management efficacy. In this study, we developed three-dimensional (3D) homogenous finite element (FE) CT-leg systems to qualitatively compare the pressure diversities along lower limbs with different biomaterial tissue properties under each external compression level. Simultaneously, through the obtained leg circumferential displacement, a contact analysis model was applied to quantitatively explore the impact mechanisms of soft leg indentations on the pressure performance of CTs. Based on the experimental validation study, the proposed FE systems could be efficiently utilized for compression performance prediction (error ratio: 7.45%). Through the biomechanical simulation and theoretical calculations, the tissue stiffness characteristics of applied bodies showed significant correlations (p < 0.05) with the body circumferential displacements but no correlations (p > 0.05) with pressure delivery differences of CTs. This study facilitates the pressure fit design principle and leg mannequin material selection guidance for the development and experimental assessment of CTs. It also provides effective simulation methods for pressure prediction and property parametric optimization of compression materials.

Super‐Resolution Two‐Photon Fluorescence Tomography Through the Phase‐Shifted Optical Beatings of Bessel Beams for High‐Resolution Deeper Tissue 3D Imaging

AbstractA novel z‐scanning‐free epi‐detected super‐resolution two‐photon fluorescence tomography (TPFT) technique enabling super‐resolution deeper tissue 3D imaging is reported. To accomplish this, a unique method is conceived by generating the phase‐shifted optical beatings of Bessel beams (PS‐OB3) with a spatial light modulator (SLM) to break the diffraction limit for enhancing both the lateral and axial resolutions as well as improving the penetration depth in TPFT for super‐resolution deeper tissue imaging. By electronically varying the optical beating frequency and the phase shifts of the beating patterns through SLM, the depth‐resolved TPF signals about the volumetric tissue are encoded in the spatial frequency domain and hence, a series of depth‐resolved TPF images can be retrieved by implementing inverse fast Fourier transform without a need of mechanical depth‐scanning. PS‐OB3 TPFT provides ≈1.3‐ and 2‐fold improvements in lateral and axial resolutions in comparison with conventional point‐scan TPF imaging. It is also illustrated that the epi‐detected PS‐OB3 TPFT imaging with inherent scattering‐resilient properties of the Bessel beams employed gives over 2‐fold improvement in imaging depth in porcine brain tissue compared to conventional point‐scan Gaussian beam TPF imaging. The z‐scanning‐free optical sectioning ability of PS‐OB3 method developed in TPFT is universal, which can be readily extended to practically any other nonlinear optical imaging modalities for super‐resolution deeper 3D imaging in biological and biomedical tissues.

Role of hydrogels in osteoarthritis: A comprehensive review.

Osteoarthritis (OA) is a chronic, degenerative, and age-related disease. It is characterized by chronic inflammation, progressive articular cartilage destruction, and subchondral bone sclerosis. The current effective treatment for OA is limited. Hydrogel is a kind of unique carrier with well-known biocompatibility, softness, and high water content among various biomaterials. Hydrogels are developed for different biomedical applications, for instance, drug delivery, and tissue engineering. To date, a variety of hydrogels-based therapies have been used in OA patients or animal models. In this review, we comprehensively summarized the potential role of hydrogels in chondrocytes proliferation, apoptosis, and inflammatory component production and discussed the impact of hydrogels on OA development. The collection of this information will help better understand the present progress of hydrogels in OA.

Multi-hierarchical nanoparticles with tunable core by emulsion polymerization processes

Nanoparticles (NPs) with functional cores are gaining research interest due to their advanced architecture. However, exposed reactive groups on NP surfaces can lead to material side reactions and biomedical tissue damage. NPs with multi-hierarchical morphologies can be synthesized by various methods; however, controlling the size and position of the functional groups using conventional and scalable methods is still a challenge. This study explores emulsion-based polymerization methods for producing multi-hierarchical NPs with varying sizes and compositions. We compared micro-, macro-, and semi-batch emulsion polymerization using 2-hydroxyethyl methacrylate (HEMA) and pentafluorophenyl methacrylate (PFMA) as co-monomers. The components present in PFMA can be substituted and are used for post-synthetic functionalization. The results suggest that the architecture of the synthesized NPs is multi-hierarchical, with the substitutable pentafluorophenyl units surrounded by HEMA monomers. Additionally, we evaluated the NPs' ability to enhance dermal drug penetration using nile red as a hydrophobic drug model. Significant variations in skin permeation enhancement properties were observed among the NPs, underscoring the impact of the synthesis method on nanocarriers' drug delivery performance.

Design and construction of poly (L-lactic-acid) nanofibrous yarns and threads with controllable structure and performances

The design and development of electrospun nanofibrous yarns (ENYs) have attracted intensive attentions in the fields of biomedical textiles and tissue engineering, but the inferior fiber arrangement structure, low yarn eveness, and poor tensile properties of currently-obtained ENYs has been troubled for a long time. In this study, a series of innovative strategies which combined a modified electrospinning method with some traditional textile processes like hot stretching, twisting, and plying, were designed and implemented to generate poly (L-lactic-acid) (PLLA) ENYs with adjustable morphology, structure, and tensile properties. PLLA ENYs made from bead-free and uniform PLLA nanofibers were fabricated by our modified electrospinning method, but the as-spun PLLA ENYs exhibited relatively lower fiber alignment degree and tensile properties. A hot stretching technique was explored to process the primary PLLA ENYs to improve the fiber alignment and crystallinity, resulting in a 779.7% increasement for ultimate stress and a 470.4% enhancement for Young's modulus, respectively. Then, the twisting post-treatment was applied to process as-stretched PLLA ENYs, and the tensile performances of as-twisted ENYs was found to present a trend of first increasing and then decreasing with the increasing of twisting degree. Finally, the PLLA threads made from different numbers of as-stretched PLLA ENYs were also manufactured with a traditional plying process, demonstrating the feasibility of further improving the yarn diameter and tensile properties. In all, this study reported a simple and cost-effective technique roadmap which could generate high performance PLLA nanofiber-constructed yarns or threads with controllable structures like highly aligned fiber orientation, twisted structure, and plied structure.

PLLA Nanosheets for Wound Healing: Embedding with Iron-Ion-Containing Nanoparticles

This article reports on polymer (PLLA, poly(L-lactic acid)) nanosheets incorporated with Fe-ion nanoparticles, aiming at using the latter nanoparticles as a source to release Fe ions. Such Fe ions should facilitate burn wound healing when such nanosheets are applied as a biomedical tissue on skin. Laser ablation in liquid phase was used to produce Fe-containing nanoparticles that, after incorporation into PLLA nanosheets, would release Fe ions upon immersion in water. Unlike most iron-oxide nanostructures, which are poorly soluble, such nanoparticles prepared in chloroform were found to have water solubility, as they were shown by XPS to be based on iron chloride and oxide phases. After incorporation into PLLA nanosheets, the ion-release test demonstrated that Fe ions could be released successfully into water at pH 7.4. Incorporation with two different metal ions (Fe and Zn) was also found to be efficient, as both types of ions were demonstrated to be released simultaneously and with comparable release rates. The results imply that such polymer nanosheets show promise for biomedical applications as potential patches for healing of burns.

Time domain diffuse Raman spectroscopy using single pixel detection.

Diffuse Raman spectroscopy (DIRS) extends the high chemical specificity of Raman scattering to in-depth investigation of thick biological tissues. We present here a novel approach for time-domain diffuse Raman spectroscopy (TD-DIRS) based on a single-pixel detector and a digital micromirror device (DMD) within an imaging spectrometer for wavelength encoding. This overcomes the intrinsic complexity and high cost of detection arrays with ps-resolving time capability. Unlike spatially offset Raman spectroscopy (SORS) or frequency offset Raman spectroscopy (FORS), TD-DIRS exploits the time-of-flight distribution of photons to probe the depth of the Raman signal at a single wavelength with a single source-detector separation. We validated the system using a bilayer tissue-bone mimicking phantom composed of a 1 cm thick slab of silicone overlaying a calcium carbonate specimen and demonstrated a high differentiation of the two Raman signals. We reconstructed the Raman spectra of the two layers, offering the potential for improved and quantitative material analysis. Using a bilayer phantom made of porcine muscle and calcium carbonate, we proved that our system can retrieve Raman peaks even in the presence of autofluorescence typical of biomedical tissues. Overall, our novel TD-DIRS setup proposes a cost-effective and high-performance approach for in-depth Raman spectroscopy in diffusive media.

Biomimetic Hydrogel Applications and Challenges in Bone, Cartilage, and Nerve Repair.

Tissue engineering and regenerative medicine is a highly sought-after field for researchers aiming to compensate and repair defective tissues. However, the design and development of suitable scaffold materials with bioactivity for application in tissue repair and regeneration has been a great challenge. In recent years, biomimetic hydrogels have shown great possibilities for use in tissue engineering, where they can tune mechanical properties and biological properties through functional chemical modifications. Also, biomimetic hydrogels provide three-dimensional (3D) network spatial structures that can imitate normal tissue microenvironments and integrate cells, scaffolds, and bioactive substances for tissue repair and regeneration. Despite the growing interest in various hydrogels for biomedical use in previous decades, there are still many aspects of biomimetic hydrogels that need to be understood for biomedical and clinical trial applications. This review systematically describes the preparation of biomimetic hydrogels and their characteristics, and it details the use of biomimetic hydrogels in bone, cartilage, and nerve tissue repair. In addition, this review outlines the application of biomimetic hydrogels in bone, cartilage, and neural tissues regarding drug delivery. In particular, the advantages and shortcomings of biomimetic hydrogels in biomaterial tissue engineering are highlighted, and future research directions are proposed.

A bioinspired synthetic fused protein adhesive from barnacle cement and spider dragline for potential biomedical materials

Biomaterials with excellent biocompatibility, mechanical performance, and self-recovery properties are urgently needed for tissue regeneration. Inspired by barnacle cement and spider silk, we genetically designed and overexpressed a fused protein (cp19k-MaSp1) composed of Megabalanus rosa (cp19k) and Nephila clavata dragline silk protein (MaSp1) in Pichia pastoris. The recombinant cp19k-MaSp1 exhibited enhanced adhesion capability beyond those of the individual proteins in both aqueous and non-aqueous conditions. cp19k-MaSp1 protein fiber scaffolds prepared through electrospinning have adequate hydrophilicity compared to cp19k and MaSp1 protein fiber scaffolds, and offer improved overall porosity compared to MaSp1 protein fiber scaffolds. The cp19k-MaSp1 protein fiber scaffolds showed excellent proteolytically stable properties because of only 9.6 % depletion after incubation in a biodegradation solution for 56 d. The cp19k-MaSp1 protein fiber scaffolds present remarkably high extreme tensile strength (112.7 ± 11.6 MPa) and superior ductility (438.4 ± 43.9 %) compared with cp19k (34.4 ± 8.1 MPa, 115.4 ± 32.7 %) and MaSp1 protein fiber scaffolds (65.8 ± 9.3 MPa, 409.6 ± 23.1 %), also 68.4 % of tensile strength was recovered by incubation in K+ buffer after multiple stretches, which create a favorable cell adhesion, growth, and proliferation environment for human umbilical vein endothelial cells (HUVECs). The improved biocompatibility, extensive adhesion, mechanical strength, and self-recovery properties make the bioinspired synthetic cp19k-MaSp1 a potential candidate for biomedical tissue reconstruction.

Regeneration of Buccal Wall Defects after Tooth Extraction with Biphasic Calcium Phosphate in Injectable Form vs. Bovine Xenograft: A Randomized Controlled Clinical Trial.

Bone healing after tooth extraction may be affected by defects of the alveolus buccal wall, such as fenestrations and dehiscences. Therefore, to minimize dimensional changes it is advisable to perform alveolar ridge preservation after tooth extractions. Different biomaterials are used for this purpose. The aim of this study was to investigate the qualitative and quantitative histological changes in human biopsies taken after 6 months of healing of extraction sockets with buccal wall defects. For this purpose, the defects of 36 patients (18 per group) were treated with injectable biphasic calcium phosphate (I-BCP) or bovine xenograft (BX) after extraction. After six months of healing, biopsies were taken and proceeded to the histology laboratory. No evidence of an inflammatory response of the tissue was observed in the biopsies of either group, and the newly formed bone (NB) was in close contact with the remaining biomaterial (BM). The histomorphometric results showed that there was no statistically significant difference between the groups in the mean percentage of NB (p = 0.854), BM (p = 0.129), and soft tissue (p = 0.094). To conclude, both biomaterials exhibited osteoconductivity and biocompatibility and achieved satisfactory bone regeneration of buccal wall defects after tooth extraction.

A novel biomimetic nanofibrous cardiac tissue engineering scaffold with adjustable mechanical and electrical properties based on poly(glycerol sebacate) and polyaniline

Biomaterial tissue engineering scaffolds play a critical role in providing mechanical support, promoting cells growth and proliferation. However, due to the insulation and inappropriate stiffness of most biomaterials, there is an unmet need to engineer a biomimetic nanofibrous cardiac tissue engineering scaffold with tailorable mechanical and electrical properties. Here, we demonstrate for the first time the feasibility to generate a novel type of biocompatible fibrous scaffolds by blending elastic poly(glycerol sebacate) (PGS) and conductive polyaniline (PANI) with the help of a nontoxic carrier polymer, poly (vinyl alcohol) (PVA). Aligned and random PGS/PANI scaffolds are successfully obtained after electrospinning, cross-linking, water and ethanol wash. Incorporating of different concentrations of PANI into PGS fibers, the fibrous sheets show enhanced conductivity and slower degradation rates while maintaining the favorable hemocompatibility. The elastic modulus of the PGS/PANI scaffolds is in the range of 0.65–2.18 MPa under wet conditions, which is similar to that of natural myocardium. All of these fibrous mats show good cell viability and were able to promote adhesion and proliferation of H9c2 cells. Furthermore, the in vivo host responses of both random and aligned scaffolds confirm their good biocompatibility. Therefore, these PGS/PANI scaffolds have great potential for cardiac tissue engineering.

Study on the influence of temperature and strain rate on the tensile behavior of Ti–5Mo–5Cu alloy biomaterial alloy: a molecular dynamics simulation

The development of efficient biomedical bone tissue implants has invoked significant impact in the biomedical research fields and aids the aged populated peoples. In this examination, the mechanical features of implant material (Ti–5Mo–5Cu alloy) has been investigated using the molecular dynamics method under varying temperature and strain rate to understand its physical phenomenon and through this study, it is found that the strain rate has offered a complex beneficial impact over the material characteristics such as yield stress and yield strain, owing to its higher impact over the restraining behavior between various atoms and strain toughening effect related to the temperature effect. Furthermore, the shear strain and point defect analysis has confirmed that the structural alteration and the establishment of multiple dislocations lead to induce the deformation behavior of Ti–5Mo–5Cu biomaterial alloy. Additionally, the radial distribution analysis has stated that the introduction of higher ambient temperature leads to invoking multiple dislocations which are responsible for the deformation behavior and cause the major reduction in tensile properties.

Magneto-responsive hyaluronan hydrogel for hyperthermia and bioprinting: Magnetic, rheological properties and biocompatibility.

Magneto-responsive soft hydrogels are used for a number of biomedical applications, e.g., magnetic hyperthermia, drug delivery, tissue engineering, and neuromodulation. In this work, this type of hydrogel has been fabricated from hyaluronan (HA) filled with a binary system of Al2O3 nanoparticles and multicore magnetic particles (MCPs), which were obtained by clustering of superparamagnetic iron oxide FeOx NPs. It was established that the presence of diamagnetic Al2O3 has several positive effects: it enhances the hydrogel storage modulus and long-term stability in the cell cultivation medium; prevents the magnetic interaction among the MCPs. The HA hydrogel provides rapid heating of 0.3 °C per min under exposure to low amplitude radio frequency alternating magnetic field. Furthermore, the magneto-responsive hydrogel was successfully used to encapsulate cells and extrusion-based 3D printing with 87±6% cell viability, thus providing a bio-ink. The combination of high heating efficiency, softness, cytocompatibility, and 3D printability of magnetic HA hydrogel leads to a material suitable for biomedical applications.

Smart shape memory polymers and their significance in biomedical applications: A review

AbstractShape‐memory polymers (SMP) are materials responsive to stimuli, which will be modified to their initial form on the occurrence of an appropriate input. SMPs have been a class of impulsively valuable material in the last few decades. Because of their numerous, adaptable uses across a wide range, “wise” materials (SMPs) have attracted intense interest in the advanced material fields. Besides others, they need a substantial part of the area of the medical field. SMPs provide flexibility for promoting keyhole surgery, which offers stable strength, imposes stabilization forces, rinse therapeutic agents, and are degradable. Basic research on proposed SMP systems for medicine emphasizes biocompatibility, tolerability, disinfection, and non‐toxicity. This article mentions an overview of the latest advancements in the applications of SMP been reported. The article aims to incorporate all the possible applications of SMP, making it a versatile material that juxtaposes it with other advanced materials. The significance of SMP in the biomedical field, drug development, cardio‐vascular diseases, tissue engineering, wound dressing, surgical sutures, and many other applications has been highlighted. Another section dedicated to the antimicrobial abilities of SMP has been discussed. The last section is devoted to the conclusion and future developments in the respective area. Thus, this review focuses on many biomedicine areas and tube, medical science, and neuronic applications regarding the development and ability of SMPs to boost the quality of services in these fields.

Evaluation of Biocompatibility of PLA/PHB/TPS Polymer Scaffolds with Different Additives of ATBC and OLA Plasticizers.

One of the blends that is usable for 3D printing while not being toxic to cell cultures is the lactic acid (PLA)/polyhydroxybutyrate (PHB)/thermoplastic starch (TPS) blend. The addition of plasticizers can change the rate of biodegradation and the biological behavior of the material. In order to evaluate the potential of the PLA/PHB/TPS material in combination with additives (plasticizers: acetyl tributyl citrate (ATBC) and oligomeric lactic acid (OLA)), for use in the field of biomedical tissue engineering, we performed a comprehensive in vitro characterization of selected mixture materials. Three types of materials were tested: I: PLA/PHB/TPS + 25% OLA, II: PLA/PHB/TPS + 30% ATBC, and III: PLA/PHB/TPS + 30% OLA. The assessment of the biocompatibility of the materials included cytotoxicity tests, such as monitoring the viability, proliferation and morphology of cells and their deposition on the surface of the materials. The cell line 7F2 osteoblasts (Mus musculus) was used in the experiments. Based on the test results, the significant influence of plasticizers on the material was confirmed, with their specific proportions in the mixtures. PLA/PHB/TPS + 25% OLA was evaluated as the optimal material for biocompatibility with 7F2 osteoblasts. The tested biomaterials have the potential for further investigation with a possible change in the proportion of plasticizers, which can have a fundamental impact on their biological properties.

Characterization of the angular memory effect of dynamic turbid media.

The optical angular memory effect (AME) is a basic feature of turbid media and defines the correlation of speckles when the incident light is tilted. AME based imaging through solid scattering media such as ground glass and biomedical tissue has been recently developed. However, in the case of liquid media such as turbid water or blood, the speckle pattern exhibits dynamic time-varying characteristics, which introduces several challenges. The AME of the thick volume dynamic media is particularly different from the layer scatterers. In practice, there are more parameters, e.g., scattering particle size, shape, density, or even the illuminating beam aperture that can influence the AME range. Experimental demonstration of AME phenomenon in liquid dynamic media and confirm the distinctions will contribution to complete the AME theory. In this paper, a dual-polarization speckle detection setup was developed to characterize the AME of dynamic turbid media, where two orthogonal polarized beams were employed for simultaneous detection by a single CCD. The AME of turbid water, milk and blood were measured. The influence of thickness, concentration, particle size and shape, and beam diameter were analyzed. The AME increasement of upon the decrease of beam diameter was tested and verified. The results demonstrate the feasibility of this method for investigating the AME phenomenon and provide guidance for AME based imaging through scattering media.

Multi-material electrospinning: from methods to biomedical applications.

Electrospinning as a versatile, simple, and cost-effective method to engineer a variety of micro or nanofibrous materials, has contributed to significant developments in the biomedical field. However, the traditional electrospinning of single material only can produce homogeneous fibrous assemblies with limited functional properties, which oftentimes fails to meet the ever-increasing requirements of biomedical applications. Thus, multi-material electrospinning referring to engineering two or more kinds of materials, has been recently developed to enable the fabrication of diversified complex fibrous structures with advanced performance for greatly promoting biomedical development. This review firstly gives an overview of multi-material electrospinning modalities, with a highlight on their features and accessibility for constructing different complex fibrous structures. A perspective of how multi-material electrospinning opens up new opportunities for specific biomedical applications, i.e., tissue engineering and drug delivery, is also offered.