Overcoming Barriers to Transmission Electron Microscopy with Low Voltage Electron Microscopy (LVEM): A Case Study across the Caribbean, Central, and South America

Transmission Electron microscopy (TEM) is the gold standard for characterizing nano-sized structures and therefore plays a significant role in advancing research across various disciplines, including materials science, biology, and nanotechnology.Since the technique was first introduced in the 1930s, the applications of electron microscopy have developed tremendously.Electron microscopes are being widely used by researchers at universities, research institutes, and governmental agencies across the world [1].However, the distribution of these microscopes is not uniform globally.Specifically, there exists a strong dichotomy between the number of available microscopes between North America, Central, and South Americas.While there are thousands of TEMs spread around the USA and Canada, the total number of electron microscopes in the Caribbean, Central, and South American countries is only a fraction.For example, there are over 15 TEMs only in the city of Montreal, (population 1.8 million in 2025 [8]), a ratio of 8.3 microscopes per million inhabitants, while the entire country of Brazil (population 212 million in 2025 [9]) has a total of 80 [10], or 0.37 TEMs per million inhabitants.Additionally, among the countries in this region, Brazil [11] and Mexico [12] hold stronger positions, with active EM societies.A number of others, such as Argentina [13], Peru, and Costa Rica, have moderate EM development, while the majority have no or very limited EM units [14].The high costs of purchasing and maintaining Transmission Electron Microscopes are the main factors limiting their accessibility and widespread adoption [15].The major upfront costs for these instruments include the cost of acquisition, as well as the necessary infrastructure for housing and installing the microscope, including facilities specially designed to eliminate vibration and stray electromagnetic fields and housing gas and vacuum supply, and water circulators.Even after the purchase, there are annual costs related to the operation, maintenance, and repairs of the microscopes.Furthermore, these complex systems necessitate highly trained personnel to be kept on staff for the operation and maintenance of the microscopes, further increasing annual costs.All of these factors have resulted in a limited number of TEMs to be installed across Mexico, the Caribbean, Central, and South America spread over a wide geography, limiting the accessibility of such instruments for researchers [14].While High Voltage TEMs operating at accelerating voltages above 80 kV require all the infrastructure mentioned above, there exists an alternative, the Low Voltage Electron Microscope (LVEM) operating at voltages below 30 kV, which promises to increase the accessibility of the technique for a majority of research applications in the life sciences and materials sciences, by eliminating all of the aforementioned barriers.The LVEM is considerably smaller and simpler in design compared to a High Voltage TEM [16].Its acquisition cost is lower, and does not require the same infrastructure for installation.Additionally, these systems demand significantly less maintenance over time.Delong Instruments is the leader in Low Voltage Electron Microscopy, producing two main lines of instruments: the benchtop LVEM 5, operating at 5 kV with a resolution of 1.2 nm, and the compact LVEM 25E, operating at 25 kV with a resolution of 1.0 nm.Both instruments can be further equipped with SEM and STEM detectors, while the LVEM 25E also offers EDS detection capabilities.These microscopes require just a single-phase 120/220V 10A power outlet, commonly available worldwide, with no need for external pumps or water circulators, and they occupy a tiny footprint compared to other TEM instruments.Additionally, their operation and maintenance are much simpler, with the ability to be operated by users with just two to three days training.Importantly, their upfront costs are much lower than other TEMs.These advantages-lower upfront and operational costs, simpler facility requirements, and ease of use-make the LVEM an ideal solution for electron microscopy across Mexico, the Caribbean, Central, and South America.This work is a case study describing how Delong Instruments' LVEM enabled and improved EM access to universities and research institutions in Brazil [17], Chile [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], the Dominican Republic [34][35][36], Peru [37][38][39][40][41][42][43] and Puerto Rico [44], and allowed for publishing in peer-reviewed scientific journals, thereby increasing their scientific capacity and international presence.The scope of research conducted in these institutions ranges from materials science, in areas such as graphene and carbon [34], quantum carbon dots [17], polymers [31], and nanomaterials [40]; to biological science, in fields such as drug delivery [20], microbiology [28], biopolymers [30], pharmaceutics [32], biosynthesis [33], plant disease [27], and marine life research [19].In these works, LVEM was used to perform TEM, SEM, and electron diffraction (ED) [35,36].

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