Myocardium Infarction (MI) is one of the foremost cardiovascular diseases (CVDs) causing death worldwide, and its case numbers are expected to continuously increase in the coming years. Pharmacological interventions have not been at the forefront in ameliorating MI-related morbidity and mortality. Stem cell-based tissue engineering approaches have been extensively explored for their regenerative potential in the infarcted myocardium. Recent studies on microfluidic devices employing stem cells under laboratory set-up have revealed meticulous events pertaining to the pathophysiology of MI occurring at the infarcted site. This discovery also underpins the appropriate conditions in the niche for differentiating stem cells into mature cardiomyocyte-like cells and leads to engineering of the scaffold via mimicking of native cardiac physiological conditions. However, the mode of stem cell-loaded engineered scaffolds delivered to the site of infarction is still a challenging mission, and yet to be translated to the clinical setting.
Cardiovascular disease, predominantly MI, is attributed the highest mortality rate worldwide [1]. Reduced contractility and function, irregular left ventricle remodeling, and uneven stress distribution in the heart muscle are among the complications occurring post-MI, eventually resulting in catastrophic heart failure. According to the American Heart Association (AHA)’s “Heart Disease and Stroke Statistics—2021”, the prevalence of CVD (including heart failure, hypertension, and stroke) in the US population is 49.2% in the age range of 20 years and above [2]. In 2014, 150,000 people died due to MI; thus an estimated approximately 14% of global death occurs mainly due to MI. Furthermore, MI survivors are also 15 times more likely to develop post-disease complications that lead to heart failure, and are prone to die sooner rather than later compared to the normal population [1]. Cardiac ischemia-related deaths have also ascended to the top of the list of causes of death in India, the United States, and Europe, apart from MI [1][3][4]. After MI incidence, male and female patients above 45 years of age have a lower life expectancy, of 8.2 and 5.5 years, respectively [1]. Socioeconomic burdens such as health care infrastructure and treatment costs (USD 11.5 billion) have made MI one of the top ten most expensive illnesses in the United States [1][5]. Researchers and clinicians around the world have been working extensively to reduce the global incidence of MI and develop significant cost-effective treatment strategies to reduce the mortality rate from MI.
The human heart is a complex organ composed of various types of cells such as cardiomyocytes (CM), fibroblasts, endothelial cells, valve interstitial cells, and resident cardiac stem cells. The cells of the heart are very active metabolically, as it physiologically requires adenosine tri-phosphate (ATP) for its function. Nonetheless, the heart lacks endogenous repair or regeneration potential, thus it remains devoid of regenerative capacity. Any defect in size or deficiency in cardiomyocyte numbers leads to life-threatening MI-related cardiovascular complications [6]. Currently, mitigation of CVDs by pharmaceutical drugs and other clinical practices have effectively improved the patient’s survival and quality of life after tissue damage [7]. However, this remains only a short-term solution of temporary duration; the permanent curative would be via heart transplant. Severe shortage of donor organs, post-graft complications, and the limited efficacy of pharmacological interventions has placed the emphasis on cell-loaded scaffold-based therapeutic approaches for cardiovascular complications (CVDs).
The emergence of cardiac tissue engineering (CTE) has not only given substantial hope for resolving or rescuing the damaged heart after MI but also for prompting the regeneration of the damaged myocardium, thus providing a permanent curative. The idea of CTE was first impelled in 1995 by in vitro-generated cardiac tissue obtained from embryonic chicken CMs. This further ushered in the prospect of new research areas around CTE, mainly idealised to translate the bench to bedside. CTE primarily aims to recapitulate the in vivo cardiac niche under in vitro conditions. Therefore, the long-term goals of CTE are considered the construction of in vitro-fabricated tissues for in vivo cardiac repair and regeneration, in vitro preclinical models for evaluation of drug toxicity, and disease models for understanding the development and pathophysiology of heart-related disorders [8]. With the global rise in CVD cases, it is essential to reinforce the treatment modalities for better disease management. In the current scenario, the previously mentioned CTE is considered as at the forefront; however, the conducting of numerous clinical trials is crucial in prioritizing CTE in clinical practice.
Delivery of an engineered scaffold loaded with stem cells, CM mitogens, or pharmacological molecules directly to the infarcted site via either the intra-coronary or intra-myocardial mode leads to the relatively prompt recovery of the infarcted tissue, followed by regeneration and regaining of functional significance. Still to be addressed are the current roadblocks to successive clinical utilization, such as an optimized protocol for stem cell-derived CMs and their source, biomaterials for CM cultures, as well as their delivery strategies [9]. Advanced delivery approaches using injectable or patch-based methods are recently gaining significant attention due to their complexity in design and versatility in application. The most advanced technology, using iPSC-derived CM-loaded microfluidic devices, has now been providing unprecedented opportunities to understand the mechanisms of MI development. This technology can also be employed to study the effects of drugs in the preclinical drug screening phase [10].
The recent technological advances in cardiac tissue engineering, for example, cell-based therapy and patch-based therapy, have been elucidated in Figure 1.

Figure 1. Schematic representation of various tissue engineering approaches for MI treatment. These approaches include hydrogel-based cell delivery (left hand corner), patch-based cell delivery (middle panel), and microfluidics-based drug screening (right corner) during the regenerative therapy of damaged heart tissue.


| Initial Cell Type | Target Cell Type | Composition of Delivery Vehicle | Mode of Delivery | Animal Models | Outcomes | Limitations | References |
|---|---|---|---|---|---|---|---|
| iPSCs | CMs | Polyethylene glycol hydrogel | Trans-epicardial | MI in nude rats | Increased infarct thickness and improved muscle content | No donor cell engraftment was observed | [25] |
| Mouse ESCs | CMs | PA-RGDS based gel | Trans-epicardial | Mice | Engraftment and integration of mESC-CMs into host myocardium improved cardiac function |
No information available on cardiac remodelling | [12] |
| iPSCs | CMs | PBS solution | Trans-epicardial | Post-infarcted swine | Enhanced angiogenesis, reduced apoptosis, and blunted cardiac remodelling | No detailed information available on the engraftment of donor cell | [26] |
| MSCs | **** | Self-assembling peptide hydrogels (3-D Matrix, Ltd.) | Surface immobilization by spreading | Lewis rats | Augmented microvascular formation and reduced interstitial fibrosis | No detailed information available on the engraftment of donor cell and CMs differentiation from MSC | [27] |
| MSCs | **** | Si-HPMC | Trans-epicardial | Lewis rats | Short-term recovery of ventricular function and attenuated mid-term remodelling | No detailed information available on the engraftment of donor cell and CMs differentiation from MSC | [28] |
| c-Kit overexpressing CSCs | **** | PBS solution | Intracoronary | Fischer 344 rats | Preserved LV function and structure | Increased cell dose was found to be harmful. Cell tracing or engraftment were not available in detail | [28] |
| CSCs | **** | Matrigel and dimethylpolysiloxane mixture gel | Trans-epicardial | NOD-SCID mice | Improved long-term retention of CSCs, cardiac structure and function | Cell tracing or engraftment were not available | [29] |
Figure 54. Steps in microfluidic cardiac model generation—(a) Selection of cells and extracellular matrix are performed based on the physiology to be studied; (b) this is followed by design of the chip through different computational software to achieve the desired flow contours; (c) based on the design, the device is fabricated by various microfabrication procedures (the most common being photolithography; the steps of which are 1. spin coating of clean silicon wafer, 2. UV exposure with a mask, 3. dissolution of unwanted resist with developer solution to generate the master pattern, 4. PDMS mold creation from the master pattern, 5. punching of required inlet and outlet holes in the PDMS mold, and 6. bonding of the PDMS mold with a glass plate or another PDMS slab to close the device); (d) introduction of cell-laden hydrogel into the device for 3D culture (its selection is based on the mechanical properties needed for the micro tissue under study; (e) completion of the electrical circuit required for stimulation of the cardiac cells; (f) integration of the device with external circuitry and pumping mechanism for seamless operation of the chip [33][34][35][36].