and the challenges associated with their fabrication, materials, and regulatory approval [2,10]. Overall, these studies underscore the transformative potential of microneedle patches in enhancing drug delivery efficiency, improving patient comfort, and expanding healthcare accessibility.

Figure 1 highlights the potential applications of microneedle technology in healthcare, with a focus on targeted drug delivery systems, depicted through detailed anatomical and physiological illustrations including the skin's response to microneedle penetration and the related biological processes.

Figure 1: Potential applications of microneedle technology in healthcare

Revolutionizing Vaccine Delivery

The concept of microneedles was proposed in the 1970s, but it wasn't until the 1990s that it was experimentally demonstrated. This was made possible by the microfabrication tools provided by the microelectronics industry, which allowed for the creation of such small structures. Since the first studies on transdermal drug delivery in 1998 there has been a growing interest in the field [11]. Most of the activity has been focused on the development of novel needle fabrication technologies within the microfabrication community and the creation of microneedles for pharmaceutical applications within the drug delivery industry [12].

Transdermal drug delivery is a noninvasive method of administering biologically active agents through the skin for local or systemic effects. It can be self-administered and offers several advantages. However, there are certain requirements for drugs that are suitable for transdermal administration. For example, the maximum molecular weight should not exceed 1000 Da, and there should be a balance between hydrophobicity and polarity to overcome the barrier posed by the stratum corneum [13].

Most protein and peptide drugs, due to their hydrophilic and macromolecular nature, face difficulties in penetrating the skin. In recent decades, various chemical and physical methods have been developed to enhance transdermal drug permeation. These methods include the use of penetration enhancers [14], microjet technology [15], laser [13], electroporation [16], sonophoresis [17], and iontophoresis [18]. However, these techniques are often expensive and cumbersome to use, and their efficiency in facilitating the successful transdermal delivery of macromolecular drugs remains limited [19].

One of the most promising applications of microneedle technology is in vaccine administration. Traditional vaccination methods often face challenges such as the need for skilled healthcare workers, the risk of needle-stick injuries, and the complexities of biomedical waste management. Microneedle patches offer a compelling solution by simplifying the vaccination process and eliminating the need for hypodermic needles [20].

A notable advancement in this field is the development of microneedle patch tested in the Gambia [21]. This patch represents a significant stride toward improving vaccine accessibility and efficacy in regions plagued by healthcare delivery challenges. The patch's ease of use and storage, coupled with its ability to administer vaccines without traditional syringes, promises to increase vaccination rates in hard-to-reach populations, thereby enhancing community health resilience.

Enhancing Chronic Disease Management

Microneedle technology also plays a critical role in the management of chronic diseases, such as diabetes [22]. Traditional management techniques, which often require frequent blood sampling, can be cumbersome and painful for patients. Microneedle patches, however, facilitate non-invasive monitoring of physiological markers. For example, a microneedle patch developed for diabetic diagnosis can monitor multiple biomarkers simultaneously, offering a more comprehensive and less invasive alternative to conventional glucose testing methods.

This technological innovation not only improves patient comfort but also provides real-time data that can lead to more precise and timely adjustments in therapy. Such advancements have the potential to transform chronic disease management by enhancing the accuracy of diagnoses and the efficacy of treatments. This can improve accessibility and reduce healthcare costs.

Advancing Dermatological Treatments

In the field of dermatology, microneedle patches enhance the delivery of cosmetic and therapeutic agents directly into the skin [23]. These patches are used for a variety of purposes, including skin regeneration, anti-aging treatments, and the reduction of scar formation. For instance, a novel core-shell microneedle patch has been developed for scarless skin repair, delivering bioactive compounds that promote tissue regeneration and reduce inflammation.

These dermatological applications highlight the dual benefits of microneedle patches: targeted therapy with minimal systemic exposure and enhanced patient acceptance due to reduced pain and discomfort. By providing a controlled release of therapeutic agents, these patches ensure effective treatment while minimizing side effects, thereby offering a superior alternative to traditional topical applications and injections.

Addressing Social Stigma and Healthcare Challenges

While microneedle technology offers numerous benefits, it also faces unique challenges, particularly in addressing the social stigma associated with certain treatments [14]. For example, the management of leprosy using clofazimine has resulted in skin hyperpigmentation, which can lead to social stigma and isolation. Microneedle patches could potentially deliver similar therapeutic effects with reduced cosmetic side effects, thereby mitigating these social challenges.

Furthermore, the development and implementation of microneedle technology must navigate issues related to patient education, regulatory approval, and manufacturing challenges. Ensuring the quality and safety of these patches is paramount to their success and acceptance in global health markets.

Strengths and limitations of microneedle technology

Microneedles have the potential to enhance patient compliance and overcome the skin barrier for the delivery of protein and peptide drugs. Microneedles have been developed in various designs and

with different delivery strategies. These designs can be broadly categorized as solid microneedle, coated microneedles, hollow microneedles, dissolving microneedles, and hydrogel-forming microneedles. The skin plays a unique role in biology and immunomodulation. Its active immune environment can work in synergy with microneedles-mediated vaccine delivery to combat infectious diseases and treat cancers. Microneedles also have important applications in diabetes treatment, enabling safer closed-loop glucose-responsive therapies. Furthermore, microneedle mediated transdermal delivery of checkpoint inhibitors has demonstrated reduced off-target effects and achieved localized targeted delivery for the treatment of superficial cancers [24]. In summary, microneedle hold great promise as a strategy for the delivery of protein and peptide drugs to treat a wide range of diseases. However, there are some limitations to microneedle technology. Microneedles have a limited ability to penetrate the skin deeply, which may restrict their use for medications that require deeper delivery. Additionally, the fabrication of microneedle arrays (MNA) with precise dimensions and structures can be complex and expensive, which limits their widespread adoption. The effectiveness of microneedle delivery may also vary depending on factors such as skin thickness, hydration level, and individual anatomical differences among patients. While microneedles are minimally invasive, there is still a risk of infection if proper sanitation procedures are not followed during application. Moreover, microneedles have a limited capacity to deliver large volumes of drugs or vaccines.

Conclusion

Microneedle technology represents a significant leap forward in the field of medicine, offering less invasive, more accessible, and potentially more effective treatments across various domains of healthcare. From revolutionizing vaccine delivery in resource-limited settings to enhancing chronic disease management and advancing dermatological treatments, microneedle patches have the potential to reshape standard medical practices and improve global health outcomes.

As we continue to witness the evolution of this technology, ongoing research and development will be crucial in overcoming existing challenges and maximizing the therapeutic potential of microneedle patches. The continued collaboration between researchers, healthcare providers, and regulatory bodies will be essential to ensure that this innovative technology reaches its full potential in improving patient care worldwide.

Table 1: Overview of key studies of microneedle technology

Supporting information

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Ethical Considerations

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Acknowledgments

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Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Author contribution statement

All authors contributed equally and attest they meet the ICMJE criteria for authorship and gave final approval for submission.

Data availability statement

Data included in article/supp. material/referenced in article.

Additional information

No additional information is available for this paper.

Declaration of competing interest

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

References